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This is the Change Log for PHPlot.

The project home page is http://sourceforge.net/projects/phplot/

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2015-11-03 ===== Released as 6.2.0 =====

    * phplot.php: Updated version comment

    * README.txt: Updated for new release

    * NEWS.txt: Add text for new release

2015-10-31

    * Feature Request #58 "data borders for area plot types":

      Moved the code for data borders from DrawSquaredArea() into a new

      internal function DrawAreaFillBorders(). Use that function in both

      DrawSquaredArea() and DrawArea() to implement data borders for all 4

      plot types (area, stackedarea, squaredarea, and stackedsquaredarea).

      Note: There is a problem with the data borders in area and squaredarea

      plots, when the data values are not decreasing in Y. The areas overlap

      but the data borders are drawn without regard for the overlap. This is

      not from this change, but the previous change which implemented data

      borders for squaredarea plots. More on this to come.

2015-10-30

    * Fixed comments on functions and variables for data borders, which are

      no longer used only for bar and stackedbar plot types.

2015-10-25

    * Feature Request #57 "squarefilled plot type":

      + Defined 2 new plot types: squaredarea and stackedsquaredarea.

      + Added new internal function SetupAreaPlot() which sets up for an

        area fill plot, using code moved from DrawArea().

      + Changed DrawArea() to use SetupAreaPlot(). Also fixed mis-named

        variables: row versus column.

      + Added new internal function DrawSquaredArea() to draw the new plot

        types squaredarea and stackedsquaredarea.  This uses the new

        SetupAreaPlot(), draws the area fills and optional border.

2015-10-22

    * Changed version to 6.2.0-unreleased (was: 6.1.1-unreleased).

    * Feature Request #56 "Hidden Y values when zero":

      Extended the 'printf' label formatting type by allowing 1-3 format

      strings. Selection of a format string depends on the sign of the value

      being formatted (similar to the way spreadsheets do cell formatting).

      This supports a wide variety of format variations, including the one

      requested in this FR, without having to use a custom function.

      + Changed SetLabelType() to accept up to 3 format strings, and store

        then in the class variable as an array.

      + Changed FormatLabel() to accept a format string, or an array of

        1, 2, or 3 format strings, and select among them based on the sign

        of the value being formatted.

2015-08-29

    * Fixed bug #172 "Fixes for PHP7":

      PHP7 (currently pre-release) deprecates the use of the class name

      as the constructor, which was how PHP4 did it. Fixed the constructor

      name to work with PHP7. Note this may affect extended classes.

2015-03-25

    * Fixed bug #170 "Replace eval():...":

      Removed the one use of eval() in PHPlot, because eval() makes people

      nervous, is incompatible with some VM setups, and the specific usage

      was hard to understand.  Changed SetDefaultDashedStyle() to create a

      string template (rather than a code string) in the class variable

      default_dashed_style. Changed internal SetDashedStyle() to apply the

      template without eval(). There is no change to the API or behavior,

      except PHPlot now validates the dashed line specification argument to

      SetDefaultDashedStyle() more thoroughly.

2015-03-21

    * Feature Request #55 "Method documentation in phpdoc format":

      Added phpdoc comments (docblocks). All class functions (methods) now

      have docblocks with summary, parameters, and return value (other than

      the old deprecated functions, which have just a @deprecated tag).

      phpDocumentor2 is able to generate documentation from the source, but

      there is no plan to use this to replace any portion of the PHPlot

      Reference Manual.

      In order to accommodate phpDocumentor2 problems with functions that take

      variable argument lists, while remaining compatible with PHP 5.5 and

      PHP 5.4, it was necessary to change the parameter lists for 5 public

      methods and 2 protected methods. No change was made to the usage of

      these functions: unused parameter names were added, with NULL defaults,

      so phpdoc '@param' tags could be used for them.

    * Mark as pre-release 6.1.1

    * Makefile: Added phpdoc target to run phpDocumentor2.

2013-05-11 ===== Released as 6.1.0 =====

    * phplot.php: Updated version comment and version constant

    * README.txt: Updated for new release, fix copyright year

    * NEWS.txt: Add text for new release

2013-04-22

    * Feature request #52 "Box Plots":

      + New plot type 'boxes'.

      + New internal method DrawBoxes() draws a box plot.

      + Added 4 new tuning variables for box plot feature size tuning.

2013-04-16

    * Mark as pre-release 6.1.0

    * Feature Request #47 "Extend horizontal plots to more types":

      Implemented horizontal error plots. (This is the remaining,

      unimplemented part the feature request.)

      + Added new datatype 'data-data-yx-error' for horizontal error plots.

      + Added new internal static array $datatypes to hold information

        about the available data types.

      + Added new internal static array $datatypes_map to handle the old

        data type names, and also a new alias 'data-data-error-yx'.

      + Rewrote internal DecodeDataType() to use the new array instead

        of code to set the datatype flags from the data type.

      + Changed SetDataType() to use the 2 new arrays to map and validate

        the data type.

      + Replaced internal function DrawYErrorBar() - draw one error bar

        for vertical plots - with DrawYErrorBars() and DrawXErrorBars(),

        each of which draws both parts of an error bar pair.

      + Changed DrawDots() and DrawLines() to support both vertical and

        horizontal error plots.

2013-04-03 ===== Released as 6.0.0 =====

    * README.txt: Fix PHP versions used for testing - should be 5.4.13 on

      both Linux and XP.

2013-04-02

    * phplot.php: Fixed 2 comment errors. No code changes.

    * NEWS.txt: Add 4 missing items: 2 more compatibility issues, and 2

      changes that were made along side feature requests but were not

      directly described in those requests.

2013-04-01

    Preparing for 6.0.0 release on 2013-04-03

    * phplot.php: Updated version comment and version constants

    * README.txt: Updated for new release

    * NEWS.txt: Add text for new release

2013-03-27

    * Merged /branches/Rel6 changes back into trunk. Changes recorded below

      with "(/branches/Rel6)" were made on the branch. Note: Subversion

      change history for those changes is only available by looking at

      revision 1558 on the branch, for example:

         svn log ^/branches/Rel6/phplot/phplot.php@1558

      The /branches/Rel6 tree has not been deleted, but may be in the future

      (as recommended in Subversion documentation).

2013-03-22 (/branches/Rel6)

    * Changed default minimum number of ticks intervals (min_ticks) for both

      X and Y from 5 to 8. Considering PHPlot previously used 10 intervals

      by default, 5 is just too low.

    * Numeric change to CalcStep125() - slight tweak to make the tick steps

      come out right for exact powers of 2.

2013-03-19 (/branches/Rel6)

    * Fixed bug #166 "Legend, UsePointShapes, and shape='none'":

      Added argument to DrawShape() to disallow using 'none' as a shape.  This

      is used when drawing markers in the legend. DrawShape will draw the

      'line' shape instead of 'none' in this case.

    * Code cleanup: minor cleanup in CalcMaxDataLabelSize() and

      CalcMaxTickLabelSize() in selecting 'x' vs 'y' cases.

    * Code cleanup: minor cleanup in GetDataColor().

2013-03-18 (/branches/Rel6)

    * Added adjustment factor in CalcStepBinary() to avoid round-off errors

      for a few values where log2(2^N) < N.

    * Fixed CalcPlotRange() to prevent the plot range ends from crossing

      to the wrong side of 0 when there is a tick anchor. Instead, the

      range will clip to zero, and there won't be a tick mark at that end.

    * Fixed local variable names in CalcTicks(): data_min/data_max corrected

      to plot_min/plot_max which is more descriptive.

    * Fixed bug #167 "Fails to find a default font on Ubuntu":

      Debian changed the install location for the LiberationSans fonts,

      which also affects Ubuntu and related distributions. Added a new

      entry to the default font search list in GetDefaultTTFont() so the

      font will be found at the new location.

2013-03-11 (/branches/Rel6)

    * Expanded the two modes for calculating a tick increment to three:

      decimal (1,2,5 * 10^N), date, and binary (2^N).

      + Changed member array $tickctl[] key 'datetime_interval' (boolean) to

        'tick_mode' (3 valued string).

      + New internal function CalcStepBinary() for binary mode.

      + Changed CalcStep() to select from 3 modes now, using tick_mode.

      + Changed internal function TuneAutoTicks() and public functions

        TuneXAutoTicks() and TuneYAutoTicks() parameter 'datetime_interval'

        to 'tick_mode', checked for validity.

    * Account for tick anchor when adjusting the plot range to start and

      end at a tick mark. After this change, the range will start and end

      at a tick mark (when in the default mode) even when a non-zero tick

      anchor has been set.

      + Change CalcPlotRange() so that when adjusting the range endpoints

        to the next tick mark, it uses tick_anchor in the equation. It will

        not adjust through zero, though. (Example: Range 0-10, tick anchor

        at 1, resulting range will start at 0, not -9, so the range in this

        case will not start at a tick mark.)

    * Code cleanup: Avoid use of variable property names such as

      '$this->{"num_$which" . "_ticks"}' to refer to either num_x_ticks or

       num_y_ticks, depending on $which. Although these work and are more

       compact, they make debugging harder (e.g. trying to find everywhere

       num_x_ticks is used can overlook these).

2013-03-01 (/branches/Rel6)

    * Changes to range and tick calculations, still trying to get more

      cases to come out right.

      + Add per-plot-type tuning variable plots[]['adjust_type']. This is

        to address the issue that some plot types need extra room around

        the data points, and some do not.

      + Moved the 6 class variables for tuning range and tick calculations

        into 2 arrays $rangectl[] and $tickctl[], to make it easier to

        access especially for new tuning functions.

      + Added 2 new public functions for tuning plot range:

        TuneXAutoRange() and TuneYAutoRange().

        These are implemented by a new internal function TuneAutoRange().

      + Added 2 new public functions for tuning tick calculations:

        TuneXAutoTicks() and TuneYAutoTicks().

        These are implemented by a new internal function TuneAutoTicks().

      + New internal function GetRangeEndAdjust() which implements the new

        per-plot-type default for range end adjustment.

      + Changed usage of internal CalcStep(), which now gets parameters

        directly from the new class variable arrays.

      + Rewrote CalcPlotRange() - use the new class variable arrays, and

        now implements 3 methods for adjusting the range endpoints.

    Note: This is almost done. There is one known issue with tick anchors.

2013-01-19 (/branches/Rel6)

    * Minor changes related to range and tick calculations.

      + Changed FindDataLimits() results for 'implied' range case to include

        the margins, so CalcRangeInit() does not have to adjust them now.

      + Simplified usage of internal CalcRangeInit().

      + Moved debug_scale callbacks from CalcStep() and CalcPlotRange() to

        caller CalcPlotAreaWorld(), to make it more consistent with 5.8.0.

2013-01-17 (/branches/Rel6)

    * More changes for feature request #29 "Finer control over plot element

      colors":

      + Added new method SetLegendBgColor() to set the legend background

        color, overriding the image background color.

      + Added new method SetLegendTextColor() to set the legend text color,

        overriding the general text color.

      + Added new class variables for above: legend_bg_color, legend_text_color,

        ndx_legend_bg_color, ndx_legend_text_color.

      + Changed SetColorIndexes() to allocate and default the new colors.

      + Changed DrawLegend() to use the new colors.

2013-01-02 (/branches/Rel6)

    * Extend copyright years to 2013.

    * Changed the static plots[] class variable element 'draw_axes' (default

      if absent is True) to 'suppress_axes' (default if absent is False).

    * In DrawGraph(), don't use extract() on the whole static plots[] array

      entry when only 3 variables are used. Access each needed variable.

2012-12-27 (/branches/Rel6)

    * Added constant PHPlot::version_id which is an integer (vs

      PHPlot::version which is a string). This is for the test suite so it

      can check for a minimum version. For PHPlot-6.0.0 the value is 60000.

2012-12-23 (/branches/Rel6)

    * Feature request #50 "Control legend colorbox borders":

      + Added new method SetLegendColorboxBorders($mode) to control the color

        and presence of legend color box borders. The default behavior is

        backward compatible (color box borders use Text color).

        + Added new class variable: legend_colorbox_borders.

        + Changed DrawLegend() to add new controls for color box borders.

      + Added new method SetDrawDataBorders() to enable or disable data

        borders on bars and stackedbars plots. This makes it possible to have

        the same appearance for the legend color boxes and the data bars, for

        both shaded and unshaded plots. The default behavior is backward

        compatible (borders for unshaded, no borders if shaded).

        + Added new class variable: draw_data_borders

        + Changed usage of internal GetBarColors() to return both shade and

          border colors (they were never both needed before).

        + Change usage of internal DrawBars() to take both shade and border

          colors, and to control border drawing using the new flag.

        + Changed 4 bar-chart drawing functions to get both shade and border

          color and pass both to DrawBar().

    * Feature request #51 "Lines instead of colorboxes in legend":

      Extended the use of SetLegendUseShapes() to apply to more plot types.

      For lines and squared plots, this will replace the color boxes in the

      legend with short line segments, with color, style, and width. The new

      behavior is backward compatible, as SetLegendUseShapes(True) only

      worked with points and linepoints plots before.

      + Added a new optional key to the internal static $plots array called

        'legend_alt_marker' to indicate the type of alternate marker that

        can be used in the legend for this plot type, if any.

      + Changed description of SetLegendUseShapes(), which applies to more

        plot types now.

      + Changed return variables from internal GetLegendSizeParams() to

        replace do_colorbox with the more general colorbox_mode. Also, this

        function implements the 4x scale-up on the color box width for 'line'

        mode.

      + Changed usage of internal SetDashedStyle() to streamline all the

        places where line styles are available.

      + Changed functions using styled lines per new SetDashedStyle() usage:

        Draw[XY]Ticks(), Draw[XY]DataLine(), DrawLines(), DrawSquared().

      + Changed DrawLegend() code for shape vs color box. Don't use

        point_counts to determine if point shapes should be used - use the

        new key in $plots[].  Implement line shape markers, including color,

        width and style.

    * Unrelated fix, found when testing above changes:

      + Added a work-around in DrawBar() when drawing a bar with height 0.

        The GD function for drawing unfilled rectangles puts "whiskers" at the

        ends when height is 0 (see PHP bug #53154), so draw a line instead.

2012-09-23 (/branches/Rel6)

    * Bug #164 (old #3557510) "Calculated defaults applied to subsequent

      plots":

      Fixed for X and Y data label formats.

      + CheckLabels(): Don't copy X or Y entries to XD or YD as defaults,

        because these will stick for additional plots.

      + FormatLabel(): Use the X or Y entries when XD or YD are needed

        but found to be empty.

2012-09-18 (/branches/Rel6)

    * Feature request #47 "Extend horizontal plots to more types":

      Implemented horizontal form of lines, points, and linepoints plots

      (using data types data-data-yx and text-data-yx). Merged error plot

      cases into drawing functions for lines and points.  As a side effect,

      data value labels now work with error plots.  (Note: Horizontal error

      plots are not available, but could be added without much work.)

      + Rewrote internal DrawDots() to draw error bars and horizontal plots

        too.  Removed internal DrawDotsError() which is now unused.

      + Rewrite internal DrawLines() to draw error bars and horizontal plots

        too.  Removed internal DrawLinesError() which is now unused.

      + Changed usage of internal DrawYErrorBar(): removed error_bar_type

        argument because this is always the class variable error_bar_shape.

      Implemented Y data label lines, for horizontal plots.

      + New public function SetDrawYDataLabelLines()

      + New internal function DrawYDataLine()

      + Added argument to internal DrawYDataLabel() for plot types that

        support data label lines, and call DrawYDataLine() if enabled.

      + Changed DrawDots() and DrawLines() to request data label lines

        for horizontal plots too.

2012-09-12 (/branches/Rel6)

    * Feature request #46 "Control pie chart borders":

      Added a separate color control for pie chart segment borders (vs

      over-used Grid color), and a flag to enable or disable the borders.

      Borders now work with shaded pie charts too. The defaults are

      compatible: no borders for shaded pie charts, borders using grid

      color for unshaded pie charts.

      + New function SetPieBorderColor($color)

      + New function SetDrawPieBorders($draw)

      + Added separate color index value for pie chart borders, defaulting

        to the grid color index.

      + Changed DrawPieChart() to use the new controls, including

        new ability to have borders with shaded pie charts.

2012-09-10 (/branches/Rel6)

    * Fixed bug #165 "Missing axis labels on some empty plots":

      Don't skip the body of DrawLines(), DrawLinesError(), DrawSquared(),

      or DrawBubbles() when the data column count is zero. Even though there

      are no points to plot, the outer loops need to run in order to get

      the X axis data labels drawn.

    Note: Bug and Feature Request numbers above this point refer to the

    new "Sourceforge2" trackers (low numbers). Below this point, the older

    tracker numbers (large numbers, unique across all trackers) are used.

2012-08-27 (/branches/Rel6)

    Ongoing effort to provide 'reset to default' options where missing:

    * Fixed SetTransparentColor() to accept NULL (or no argument) to mean

      reset to default - no transparency.

    * Allow missing argument to SetDefaultTTFont() to mean the same thing

      as NULL - reset to default TrueType font name.

2012-08-20 (/branches/Rel6)

    * Declare all class variables at top, initialize where valid, and make

      most PHPlot class variables 'protected' rather than 'public' visibility.

      This is a significant change, and undoes the change of 2012-06-14

      below ("Code cleanup: Avoid static initialization of class member

      variables that can just as well be unset by default").

      All variables listed in the "Tuning Parameters" section of the manual

      remain public. In addition, the $img and $fonts member variables

      remain public, although use in scripts is discouraged. (These are

      public due to historical use, including use in the PHPlot Test Suite.)

      Compatibility warning: This will break any script that accesses PHPlot

      member variables other than those listed above as remaining public.

      Code changes were made (mostly undoing changes from 2012-06-14) to

      account for variable initialization, in many places. For example,

      we can now test $this->use_ttf directly, rather than using empty() on it.

      Replace unset() with assignment to NULL where variables have a special

      state of "unspecified default".

    * Bug #3557510 "Calculated defaults applied to subsequent plots":

      Use two variables for X Data Label Angle: one for user-set value, and

      one for the effective value. This fixes a problem with multiple plots,

      where the X Data Label angle was calculated for the first plot, then

      applied to subsequent plots as if it was user-set (rather than being

      recalculated).

    * Renamed variables: x_tick_inc to x_tick_inc_u, and tick_step to

      x_tick_inc (similar for y_tick) for consistency with above X Data

      Label Angle variables. The _u suffix is set by the user; the other

      is the effective value.

    * Changed return from internal GetLegendSizeParams() - removed text_align

      and colorbox_align from the array. These were the same as the two

      class variables (with defaults applied), but now the defaults are

      initialized so there is no need to return them separately.

2012-08-14 (/branches/Rel6)

    * Code cleanup: Use 'self::' to access static properties and constants,

      rather than the actual class name.

    * Cleanup SetDefaultFonts(); no functional change.

2012-08-09 (/branches/Rel6)

    * Fixed problem with grid defaults and multiple plots. The default

      setting, to draw the grid or not, was being stored back to the class

      variables, and then this was used for the next plot rather than a new

      default being calculated. This was wrong when mixing vertical and

      horizontal plots. Removed internal CalcGridSettings() and added new

      internal GetGridSetting(), so the default is not stored back into the

      class variables.

      Also changed DrawXGrid() and DrawYGrid() to allow NULL or omitted

      argument to mean restore the default behavior.

2012-08-03 (/branches/Rel6)

    * Fixed problem with multiple plots and calculated tick increments.

      The calculated values were stored back into the object, using the same

      class variables as SetXTickIncrement() and SetYTickIncrement(). With

      subsequent plots using the same object, the calculated values were seen

      as user-provided, so new values were not calculated even if the data

      range changed. This differs from the 5.x behavior and the manual.

      Now, new class variables x_tick_step y_tick_step are used to store

      the effective values for the tick increments. If not user-set, the

      values will be recalculated for each plot.

2012-07-09 (/branches/Rel6)

    * Feature request #3541471 "Control pie chart start angle":

      Added SetPieStartAngle() and SetPieDirection(), and changed

      DrawPieChart() to work with any start angle and either direction.

2012-07-07 (/branches/Rel6)

    * Changed internal DrawText() and SizeText() to take a text element

      name (e.g. 'x_title') rather than a font name. This is actually

      implemented in the lower-level ProcessText().  For compatibility,

      however, ProcessText() still does accept a font array.  The reason for

      the change is that when using a drawing annotation callback with a pie

      chart, this makes it much easier for the callback to draw text using a

      different font than the one used for the pie chart labels.

      Changed all internal callers of DrawText() and SizeText() to pass the

      text element name rather than the $fonts[] array entry.

2012-06-26 (/branches/Rel6)

    * Fixed conflict between setting number of ticks (SetNum[XY]Ticks) and the

      new range calculations. (The range was adjusted after calculating the

      tick increment, but the tick increment depended on the range here. So if

      you asked for N tick intervals, you probably got N+1.) Moved code to

      handle pre-specified tick increment or number of ticks from CalcStep()

      to CalcPlotRange(), and let CalcPlotRange() do special handling for the

      case with number of ticks set.

2012-06-25 (/branches/Rel6)

    * Removed TuneAutoRange(). The tuning parameters will be documented as

      class variables that can be set directly, like other existing variables

      that tune things. (The problem with TuneAutoRange is that it is a new,

      3rd way to change plot settings - Set*() functions and directly changing

      a class variable being the other two. We don't need another interface.)

2012-06-20 (/branches/Rel6)

    * Fix validation in SetPlotAreaWorld(). Enforce min<max rather than

      min<=max. Allowing min==max was pointless, as it just produced an

      error later in CheckPlotRange rather than sooner in SetPlotAreaWorld.

      (Found while doing documentation updates)

2012-06-14 (/branches/Rel6)

    * Code cleanup: Avoid static initialization of class member variables

      that can just as well be unset by default. (Some variables had been

      removed in prior releases, when they needed dynamic initialization.

      So the top of the class declaration was no longer useful as

      documentation of all the class variables.) A comment was added to

      direct the reader to the Reference Manual, which documents all member

      class variables. The following class variables no longer get

      declared and initialized:

          $bar_extra_space, $bar_width_adjust, $browser_cache,

          $color_array, $draw_broken_lines, $draw_plot_area_background,

          $draw_x_data_label_lines, $grid_at_foreground,

          $group_frac_width, $is_inline, $legend, $output_file, $use_ttf,

          $x_axis_position, $x_label_angle, $y_axis_position,

          $y_data_label_angle, $y_label_angle

      Except for the minor differences noted below, there are no changes

      in behavior (provided one does not access the internal variables):

      + SetRGBArray(): Report an error if an invalid color map name is used,

        rather than just using a black and white array with no error reported.

      + Removed unneeded class variable: $color_array

      + GetLegendSize() now returns FALSE if there is no legend.

    * Code cleanup: In CalcMargins(), don't make unnecessary local copies

      of member variables.

2012-06-09 (/branches/Rel6)

    * Minor fixes for incorrect use of empty(). (Need to remember that

      empty("0") and empty(0) are true, so this cannot be used on string

      or number variables that could be "0" or 0.)

      + Fixed handling of output_file and input_file.

      + Fixed DrawMessage() - don't use empty() on color index (could be 0).

      Checked and found no other misuses of empty().

2012-06-06 (/branches/Rel6)

    * Remove obsolete file: Imagemaps.txt - This feature is now documented

      in the Reference Manual and no longer 'experimental'.

      Makefile: Remove Imagemaps.txt from release.

2012-06-01 (/branches/Rel6)

    More changes for automatic range and tick increment calculations:

    + CalcPlotRange() - renamed "top_adjust" to "end_adjust", since it

      now potentially applies to both ends of the plot range.

      Added more comments explaining some of the more opaque expressions.

      Redid adjustment of max (for positive) and min (if negative) ends

      of the plot range.  The plot range will now always begin and end at a

      tick mark. (PHPlot-5.8.0 does this, but previous changes on this

      branch made it stop ending on a tick mark.)

      Also, it will now leave more space at the ends away from zero - by

      default, at least 0.3 * tick increment (since it ends at a tick, you

      get between 0.3 and 1.3 tick increments of space). This also means

      data value labels are much less likely to run off the plot area.

    + TuneAutoRange() - renamed "top_adjust" to "end_adjust".

      Added top comments explaining the parameters in more detail.

    Note: Range ends are much better now, and as a result the PHPlot

    Test Suite results are greatly improved.

    There are still issues with tick anchors and date/time ranges.

2012-05-28 (/branches/Rel6)

    More changes for automatic range and tick increment calculations:

    + Changed internal CalcStep() usage - pass the range, not the min and

      max.  This is possible because the range checking was moved

      to CheckPlotRange().

    + New internal CheckPlotRange() makes sure the plot range is positive,

      after defaults are applied. This expands on code moved from

      CalcStep().  Called by CalcPlotRange().

    + CalcPlotRange() - renamed "zero affinity" to "zero magnet". Call

      new CheckPlotRange() to validate and adjust (if necessary) the range.

      Changed the zero magnet algorithm. This is based on some experiments

      with Libreoffice Calc charting. First, greatly increased the default

      value for zero_magnet from 0.1 (which gives 11% range expansion) to

      0.857 (or 6/7, which gives 600% range expansion). This means PHPlot

      will now expand the range up to 6 times if that would result in

      including 0 in the range.  Second, the tests were corrected, so now

      it compares the range with zero versus the original range when

      deciding whether to extend the range to include zero.

    + TuneAutoRange() - renamed "zero affinity" to "zero magnet".

    + CalcPlotAreaWorld() - pass back any error return from CalcPlotRange().

    Note: There is still work to be done on how it automatically adjusts the

    end of the range away from zero.  Currently, it tends to leave too

    little space, which is a problem with data value labels.

2012-05-09 (/branches/Rel6)

    * Incorporate in-progress changes for bug #2919086 "Improve tick

      interval calculations" and bug #1795969 "Fix automatic Y range

      calculations". This is planned for PHPlot-6.0.0.

      NOTE: This is not complete, stable, or  ready for use!

      + Remove initialization of 8 class variables: num_[xy]_ticks,

        [xy]_tick_inc, skip_*_tick. "Unset" is now the default value.

      + New internal function CalcStep125(), which calculates a tick

        increment of the form TI = K * 10 ** I, where K = 1, 2, or 5.

      + New internal function CalcStepDateTime(), which calculates a tick

        increment for date/time scales.

      + New internal function CalcStep(), which calculates a good tick

        increment given the data range and scale type, among other factors.

      + New internal function CalcRangeInit(), which provides the initial

        guesses at the plot area range limits.

      + New internal function CalcPlotRange(), which calculates the limits

        of the plot area range for either X or Y (if not user-provided).

        It also calculates the tick increment, if necessary.

      + Rewrote internal function CalcPlotAreaWorld(). This now just calls

        CalcPlotRange() twice - once for X, and once for Y.

      + Changed SetPlotAreaWorld() to validate any provided values, making

        sure the range is non-negative (which would break the later

        calculations). It now throws an error on invalid range.

      + Rewrote internal function CalcTicks(). This no longer calculates

        the tick increment, which was calculated by CalcPlotRange() because

        the range adjustment is tied to the tick increment now.

      + Remove an unneeded error check in protected function

        CalcMaxTickLabelSize().

      + Changed public functions SetXTickIncrement() and SetYTickIncrement()

        to not reset the number of tick marks.  Changed public functions

        SetNumXTicks() and SetNumYTicks() to not reset the tick increments.

        These changes are part of fixing an order-dependency problem with

        these function pairs (different result from calling SetXTickIncrement()

        then SetNumXTicks(), versus calling them in the other order).

      + New public function TuneAutoRange(). This allows setting (currently)

        5 parameters for either X or Y axis that are used to adjust the range

        and tick increment calculations. For example, one parameter sets the

        minimum number of tick intervals when the tick increment is

        automatically calculated.

2012-05-07 (/branches/Rel6)

    * Branch for Release 6.0.0. Mark as unreleased version.

2012-04-06       ===== Released as 5.8.0 =====

    * Feature request #3515519 "Support object serialize/unserialize":

      Add __sleep() and __wakeup() magic methods to support serialize

      and unserialize.

    * phplot.php: Updated version comment and version constant

    * README.txt: Updated for new release

    * NEWS.txt: Add text for new release

2012-03-31

    * Feature request #3501500 "Looping plot section":

      Implemented streaming plots (motion-JPEG).

      + New public functions StartStream(), EndStream(), PrintImageFrame().

      + New protected function DisableCaching(), code from PrintImage().

2012-03-26

    * Code cleanup: Don't format tick labels unless they are on.

      + Pass the actual tick value, not an already-formatted label, from

        Draw[XY]Ticks() to Draw[XY]Tick(), so they can format it if needed.

      + Clean up loop in DrawXTicks(), DrawYTicks(). No functional changes.

2012-03-24

    * Feature request #3488042 "Display only some data value labels":

      A custom formatting callback function for Data Value Labels will now

      receive 2 extra arguments: the data array row and column indexes for the

      point. A custom formatting callback function for Axis Data Labels will

      now receive 1 extra argument: the data array row index. This allows

      selective formatting (or skipping) of labels based on their position

      in the data array. For example, you can skip data value labels

      for some data sets, and label others.

      + Changed usage of internal CheckDataValueLabels() to combine 4

        arguments into an array. This is to correspond to the new usage of

        DrawDataValueLabel().

      + In CalcMaxDataLabelSize(), when calculating the maximum axis data

        label size, pass the row to the formatting function.

      + Changed internal FormatLabel() to pass any additional arguments to a

        custom label formatting function.

      + Changed usage of internal DrawDataValueLabel(). Added arguments for

        row and column, and combined 6 arguments into an array (because the

        argument list was already too long). Pass the row and column to

        FormatLabel() so they are available for custom label formatting.

      + Changed usage of internal DrawXDataLabel(). The row argument is now

        required, and used for custom label formatting and data label lines.

        There is a new argument $do_lines to control drawing of data label

        lines. (Previously, one argument served both purposes.)

      + Changed usage of internal DrawYDataLabel(). Add a row argument to

        pass to FormatLabel() for use in custom label formatting.

      + Changed all plotting functions that call DrawXDataLabel() or

        DrawYDataLabel() to include the new row argument.

      + Changed all functions that call CheckDataValueLabels() and

        DrawDataValueLabel() per new usage.

2012-03-16

    * Mark as unreleased version, and change minimum requirement to PHP-5.3.

      (Since PHP-5.4 is released, PHP-5.2.x will no longer be tested.)

    * Fixed bug #3506408 "Data Label Lines vs new plot types":

      Bubble plots do work with data label lines. No code change.

      OHLC plots do not work well with data label lines, so don't draw them.

2012-02-25       ===== Released as 5.7.0 =====

    * phplot.php: Updated version comment and version constant

    * README.txt: Updated for new release

    * NEWS.txt: Add text for new release

2012-02-19

    * Feature request #3442041 "Provide data for generating image maps":

      Note: This is being added as an experimental feature, subject to change

      or removal. It will not be documented in the PHPlot Reference Manual

      unless and until this becomes an accepted part of PHPlot.

      + Added a new callback 'data_points', called after each data point is

        plotted (for supported plot types). It passes information to a handler

        which can generate an <area> tag in an HTML image map.

      + Changed usage of internal function DrawDot(). Added 2 arguments, $row

        and $column, to support the data_points callback. However, the

        existing $record arg was the same as $column, so it was removed.

            Old usage: DrawDot($x_word, $y_world, $record, $color)

            Now usage: DrawDot($row, $col, $x_world, $y_world, $color)

      + Change usage of internal function DrawBar(). Added 2 arguments, $row

        and $column, to support the data_points callback.

            Old usage: DrawBar($x1, $y1, $x2, $y2, ...)

            New usage: DrawBar($row, $col, $x1, $y1, $x2, $y2, ...)

      + Changed the logic in DrawPieChart() to accommodate the data_points

        callback, which needs to happen on the last (or only) pass.

      + Changed internal functions DrawDot(), DrawBar(), DrawPieChart(),

        DrawBubbles(), and DrawOHLC() to call the data_points callback,

        sending it the coordinates it needs for each plotted point or shape.

    * New file: Imagemaps.txt - documentation for new feature

2012-02-18

    * Fixed bug #3486834 "Wrong color for data value labels":

      Use 'text' color, not 'title' color, for data value labels.

      Compatibility warning: This will change the appearance of plots that

      use SetTitleColor or SetTextColor and data value labels.

      Also includes changes for feature request #3077554 "Finer control

      over plot element colors":

      Add new controls to independently set label color types.

      + New public function: SetDataLabelColor()

      + New public function: SetDataValueLabelColor()

      + New public function: SetTickLabelColor()

      + New public function: SetPieLabelColor()

      + Add default_color_index argument to internal GetColorIndex()

      + Add code to SetColorIndexes() to default the tick label color

        and data label color to the text color, default the data value

        label color to the data label color, and default the pie label

        color to the grid color. This is backwards-compatible, except that

        the data value labels used to use the title color.

      + Use separate color index values for ticks, axis data labels,

        data value labels, and pie labels. Use title color only for titles.

2012-02-17

    * Fixed bug #3488064 "Pie label failures in locales with comma decimal":

      This contains 2 work-arounds which together should avoid the problem.

      + Changed internal method number_format() to restore the previous

        locale settings that were in place after it gets the decimal and

        thousands separators. Also, use LC_NUMERIC rather than LC_ALL to

        limit the scope of locale loading.

      + Changed internal method FormatPieLabel() to avoid a number-to-string

        conversion if there is a single label source (the most common case).

        This conversion was resulting in use of a locale-specific decimal

        point, which PHP then fails to convert back to a number when it

        tries to format it.

2012-02-05

    * Feature request #3481195 "Custom message image":

      + New public function DrawMessage() to create an image with a message.

      + Changed protected function PrintError() to now use DrawMessage().

      + New protected function SetBgColorIndexes(), split off from

        SetColorIndexes() so that DrawMessage() can set just the colors it

        needs.

      + Added optional argument $overwrite to protected functions

        DrawBackground() and DrawImageBorder(), to force drawing even if it

        seems it was already done. This is needed for DrawMessage().

      + Moved protected function DrawError() to deprecated section.

2012-01-16

    * Added missing 'return TRUE' in SetFailureImage() and 2 internal

      functions. Return values are unused, but fixed to be more consistent.

    * Fixed bug #3396931 "Top dropshadow of stacked bars is always the

      same color":

      This is a follow-on to the fix for bug #3296884, which resulted in

      drawing (not skipping) segments of size 0 in stacked bar plots. A

      side-effect of the change was that a color 'cap' was drawn at the top of

      a stack if the last value in the row was 0.  This was considered to be

      the correct behavior at the time. But based on this new bug report, and

      looking at how LibreOffice handles this case, it was decided to change

      the way PHPlot handles this.

      + Changed DrawStackedBars() and DrawHorizStackedBars() to ignore

        segments that do not increase the stack's current size. (This is

        not the same as ignoring segments of size 0, because a row can have

        both positive and negative values. Also, if the axis was moved, an

        initial 0 value will be drawn from the axis to 0.)

        Resulting changes:

        + A trailing zero value in a row will no longer result in a color cap

          on shaded bar charts (that is, the top color of the stack would

          differ from the last segment color).

        + A row with all zero values will not be drawn at all (if the axis

          remains at 0).

2012-01-15

    * Mark as unreleased version.

    * Code cleanup: combine an assign and a test when processing data array

      (11 cases), and remove 5 cases of casting the data value to double.

      (The cast was in 4 of the plot drawing functions and FindDataLimits.

      The other plot drawing functions did not do this, so it was removed for

      consistency. Removal should have no impact, although there is an odd

      case (hex value in a string) where the explicit cast would not work,

      but the new code without casting will work.)

2012-01-02       ===== Released as 5.6.0 =====

    * phplot.php: Updated version comment and version constant

    * README.txt: Updated for new release

    * NEWS.txt: Add text for new release; new file.

    * NEWS_part1.txt: Moved text for prior releases from NEWS.txt

2012-01-01

    * Extend copyright years to 2012.

2011-12-30

    * Fixed bug #3403297 "Pie chart sizing and label issues":

      Most of the pie chart label and sizing code has been rewritten.

      (Note: This documents changes in the code.  See other documentation

      for a higher-level view and user-visible changes.)

      Compatibility warning: This changes the appearance of pie charts.

      See the NEWS file with the release for more information.

    + $label_format['p'] is now used for pie label formatting

    + Removed $plot_border_type static initialization

    + New public SetPieLabelType() controls pie label source and formatting

    + $label_scale_position = 0 or False now means no pie labels

    + New internal GetTextAlignment() moves code from CheckDataValueLabels()

    + New public SetPieAutoSize() to control use of labels in sizing pies

    + CalcMargins() changed to not calculate unused title sizes for pies

    + Added arg to  internal DrawPlotBorder(), now handles pie charts too

    + New internal FormatPieLabel() to format pie chart labels

    + New internal DrawPieLabel() to draw each pie chart label

    + New internal CheckPieLabels() to apply dynamic default values

    + Rewrote much of internal DrawPieChart() to:

    ++ Can suppress labels using SetLabelScalePosition

    ++ Fix use of label_scale_position, remove 1.2x factor

    ++ Use new $pie_diam_factor controls aspect ratio of shaded pies

    ++ Fix pie size calculation, use actual aspect ratio

    ++ Pre-calculate label strings to get their sizes, if needed

    ++ Use new $pie_full_size from SetPieAutoSize() to control autosizing

    ++ Pie size accounts for largest label (if labels are outside the pie)

    ++ Leave safe_margin between labels and pie/plot area edges

    + Changed DrawGraph() to:

    ++ Skip irrelevant data and scale calculations for pie charts

    ++ Call DrawPlotBorder() even for pie charts

2011-12-10

    * Comment typo fixes (found during work on upcoming change).

2011-11-13

    * Moved duplicated code from the 2 constructors into a new function.

2011-07-30 (lbayuk)     ===== Released as 5.5.0 =====

    * phplot.php: Updated version comment and version constant

    * README.txt: Updated for new release

    * NEWS.txt: Add text for new release

2011-07-28

    * Fixed problem found in testing with bubbles plot: data array

      with no Y,Z values at all got undefined property warnings.

    * Feature request #3352301 "Bubble plots":

      + Added new data type 'data-data-xyz', which includes a Z value

        for each Y.

      + Extended CheckDataArray(), DecodeDataType() and

        FindDataLimits() to understand new data type.

      + Added new plot type 'bubbles' for bubble plots, using data

        type 'data-data-xyz'. The Z value controls the bubble size.

      + New internal function DrawBubbles() to draw bubble plot.

      + New tunable parameters bubbles_min_size and bubbles_max_size.

2011-07-25

    * Feature request #3374495 "Data URL encoding":

      + New function EncodeImage() returns the plot image as a string,

        with 3 available encodings: raw, base64, and dataurl. The dataurl

        encoding implements RFC2397 embedding of image data in a URL,

        and allows a single PHP script to produce an HTML page with the

        plot image embedded within.

      + New internal function GetImageType() for code shared between

        PrintImage() and EncodeImage().

      + New function SetFailureImage() disables the normal behavior

        where PHPlot produces an image containing an error message in

        case of a fatal error. Suppressing this is necessary when using

        the new EncodeImage(), to avoid unexpected image data on stdout.

      + New member variable suppress_error_image, set by

        SetFailureImage(), checked by PrintError() to not make an image.

2011-07-22

    Preparing for move from CVS to Subversion.

    * Makefile: Remove 'tag' target. This was unused (and CVS-specific).

    * phplot.php: Remove reference to CVS in comment and version const.

2011-07-21

    * Fixed bug #3370548 "Reverse legend line order for stackedbars":

      New function SetLegendReverse(True) to draw lines in the legend

      in order from the bottom up, rather than top down. This is

      mostly intended for stackedbars and stackedarea plots.

2011-07-04

    * Code cleanup: Removed extra loop variable $cnt from plot drawing

      functions, where it was either unused or redundant.

2011-06-12

    * Fixed bug 3312064 "PHP errors with invalid data arrays":

      PHPlot now checks the data array more carefully, to reject invalid

      arrays and prevent PHP warning or notice errors with bad data arrays.

      + SetDataValues() checks the data array argument to make sure it uses

        0-based, sequential integer indexes, and that each element is an array.

      + CheckDataArray() (called early by DrawGraph()) uses the data type for

        more specific checking.  It makes sure each row has the right number of

        entries. (E.g. text-data >=1, data-data >=2, data-data-error =2+3N.)

      + DrawArea() ('area' and 'stackedarea' plots) returns without drawing

        anything if there are < 2 rows, to avoid a PHP warning from

        ImageFilledPolygon(). The 2-row minimum requirement is now documented.

      + DrawLines(), DrawLinesError(), and DrawSquared() return without

        drawing anything if there are no data values at all, to avoid a PHP

        warning from array_fill().

      + DrawOHLC() ('ohlc', 'candlesticks', and 'candlesticks2' plots) now

        checks early that there are 4 data columns, and fails if not.  This

        is to avoid a PHP warning when assigning line thicknesses.

2011-06-05

    * Fixed bug 3312134 "Allow missing points in OHLC plots":

      You can now skip points in the 3 OHLC plot types by using empty strings

      ('') for the 4 values in the row. All rows must still have 4 values, but

      if any is non-numeric the row will be skipped.

2011-05-27 (lbayuk)     ===== Released as 5.4.0 =====

    * phplot.php: Updated version comment and version constant

    * README.txt: Updated for new release

    * NEWS.txt: Add text for new release

2011-05-25

    * Added class constant PHPlot::version with the PHPlot release version.

2011-05-23

    * Fix bug 3296884 "Undefined variable with stackedbars":

      This is part 2 of the fix. (Part 1 fixed the undefined variable error

      when the first stack was all zeros, but did not fix related problems.)

      Changed DrawStackedBars() and DrawHorizStackedBars():

      + Do not ignore zero values. A leading zero value is significant if the

        axis is moved in the direction opposite to the stack direction.  Now

        PHPlot will draw a bar segment from the axis to zero in this case.

        Also a trailing zero value will produce a color cap on shaded bars.

      + Determine each stack direction before drawing it.  This is necessary

        to be able to draw the leading 0 segment case correctly.

2011-05-21

    * Feature request #3303654 "Force tick mark at specific value":

      + New functions SetXTickAnchor and SetYTickAnchor.

      + CalcTicks() adjusts the starting tick point so that an anchor

        point, if set, will coincide with a tick mark (or would, if the

        data range were extended).

2011-05-15

    * Feature request #3291155 "More flexible legend positioning":

      You can now position the legend by specifying that any point on the

      legend box be placed at any point on the image, plot area, or relative

      to the main title.  You can get the legend box size from PHPlot, and

      use it (for example) to adjust the plot area margins.

      + Added new public function SetLegendPosition() which provides

        much move flexible control over the legend position.

      + Re-implemented SetLegendPixels() and SetLegendWorld() by

        just having them call SetLegendPosition().

      + Added new public function GetLegendSize() which returns the

        height and width of the legend box.

      + New internal function GetLegendSizeParams() with code split

        off from DrawLegend() and used by GetLegendSize() too.

      + New internal function GetLegendPosition() calculates the legend

        position. This implements all the new position modes.

      + Removed internal class variables legend_x_pos, legend_y_pos,

        and legend_xy_world. Replaced with an array: legend_pos, which

        holds the legend position parameters set by SetLegendPosition().

2011-05-08

    * Merged 5.3.2 release changes. (The two entries below this, 2011-05-01

      and 2011-04-26, came before 5.3.2, but 5.3.2 was a single patch applied

      against 5.3.1 and not against current CVS.)

2011-05-01

    * Feature request #3292825 "Use point shape markers in legend box":

      + Implement optional use of point shapes instead of color boxes in the

        legend, for use with points and linepoints plots.

      + Add new function SetLegendUseShapes() to enable use of point shapes

        in the legend.

      + New internal class variable legend_use_shapes.

      + Removed optional never-used 3rd argument to SetLegendStyle().

      + Add new internal function DrawShape() which now implements DrawDot()

        but takes device coordinates, for use by DrawLegend().

    * Fix bug #3294604 "Center vertical alignment for legend text":

      + Legend text lines are now vertically centered on the middle of