v1.3.1

• Fix GD feature detection to determine supported image format types at runtime (#4). credit to @gromgit
• Specify library name when loading, for compatibility with Tcl 8.7 (#7). credit to @PaulObermeier
• Now uses Github Actions for CI builds (#6)

Release build fixes

Release changes to patch for removal of gdlib-config tool from Ubuntu.

v1.2

* Add new rewrite_color method to GD objects that will rewrite one
  color to another.  Clean up manpage.

* Add a "delete" method to the created GD objects. The result is the
  same as doing a rename $object ""

* Add argument count validation to the width and height methods.

* Use interpreter-associated data for the next object number for
  GD objects created with a name of "#auto" rather than a global.

  Although this should not have caused any problems with multiple
  threads using tclgd simultaneously, better safe than sorry.

* New function, tclgd_imageRewriteColor, rewrites one color to another
  for indexed and truecolor images.  Not used yet.

* Fix possible memory leak in tclgd_channelNameToIOCtx

* Fix memory deallocations to use ckfree() instead of gdFree() (Issue 1)

* Correct "rectangle" method to create a non-filled rectangle.  (We were
  incorrectly calling gdImageFilledRectangle instead of gdImageRectangle.)

* Expand docs.

v1.1

* Document the alpha_blending and save_alpha methods.

* Make the "compare" method work.

* Make the "get_alpha" method, which returns the alpha component of the
  specified color index where 0 is completely opaque and 127 is
  completely transparent, work properly.

* Make "set_brush" and "set_tile" methods work properly.

* Make the "style" method work.

* Add compare_ratio method -- given a second image of identical dimensions,
  returns the ratio of identical pixels between the images.

* Upgrade to Tcl Extension Architecture (TEA) 3.8.

* Upgrade to Tcl Extension Architecture (TEA) 3.7.

* Add pixelrgb method -- given an x and a y in an image, returns the
  red, green and blue components as a list.

* Add rgb_components method -- given a color it returns a list of the
  red, green and blue components.  This is the same as invoking the
  red_component, blue_component and green_component methods and returning
  the result as a list.