NAME

       Imager::Test - common functions used in testing Imager

SYNOPSIS

         use Imager::Test 'diff_text_with_nul';
         diff_text_with_nul($test_name, $text1, $text2, @string_options);

DESCRIPTION

       This is a repository of functions used in testing Imager.

       Some functions will only be useful in testing Imager itself, while others should be useful in testing
       modules that use Imager.

       No functions are exported by default.

FUNCTIONS

   Test functions
       is_color1($color, $grey, $comment)
           Tests if the first channel of $color matches $grey.

       is_color3($color, $red, $green, $blue, $comment)
           Tests if $color matches the given ($red, $green, $blue)

       is_color4($color, $red, $green, $blue, $alpha, $comment)
           Tests if $color matches the given ($red, $green, $blue, $alpha)

       is_fcolor1($fcolor, $grey, $comment)
       is_fcolor1($fcolor, $grey, $epsilon, $comment)
           Tests if $fcolor's first channel is within $epsilon of ($grey).  For the first form $epsilon is taken
           as 0.001.

       is_fcolor3($fcolor, $red, $green, $blue, $comment)
       is_fcolor3($fcolor, $red, $green, $blue, $epsilon, $comment)
           Tests if $fcolor's channels are within $epsilon of ($red, $green, $blue).  For the first form
           $epsilon is taken as 0.001.

       is_fcolor4($fcolor, $red, $green, $blue, $alpha, $comment)
       is_fcolor4($fcolor, $red, $green, $blue, $alpha, $epsilon, $comment)
           Tests if $fcolor's channels are within $epsilon of ($red, $green, $blue, $alpha).  For the first form
           $epsilon is taken as 0.001.

       is_image($im1, $im2, $comment)
           Tests if the 2 images have the same content.  Both images must be defined, have the same width,
           height, channels and the same color in each pixel.  The color comparison is done at 8-bits per pixel.
           The color representation such as direct vs paletted, bits per sample are not checked.  Equivalent to
           is_image_similar($im1, $im2, 0, $comment).

       is_imaged($im, $im2, $comment)
       is_imaged($im, $im2, $epsilon, $comment)
           Tests if the two images have the same content at the double/sample level.  $epsilon defaults to the
           platform DBL_EPSILON multiplied by four.

       is_image_similar($im1, $im2, $maxdiff, $comment)
           Tests if the 2 images have similar content.  Both images must be defined, have the same width, height
           and channels.  The sum of the squares of the differences of each sample are calculated and must be
           less than or equal to $maxdiff for the test to pass.  The color comparison is done at 8-bits per
           pixel.  The color representation such as direct vs paletted, bits per sample are not checked.

       isnt_image($im1, $im2, $comment)
           Tests that the two images are different.  For regressions tests where something (like text output of
           "0") produced no change, but should have produced a change.

       test_colorf_gpix($im, $x, $y, $expected, $epsilon, $comment)
           Retrieves the pixel ($x,$y) from the low-level image $im and compares it to the floating point color
           $expected, with a tolerance of epsilon.

       test_color_gpix($im, $x, $y, $expected, $comment)
           Retrieves the pixel ($x,$y) from the low-level image $im and compares it to the floating point color
           $expected.

       test_colorf_glin($im, $x, $y, $pels, $comment)
           Retrieves the floating point pixels ($x, $y)-[$x+@$pels, $y] from the low level image $im and
           compares them against @$pels.

       is_color_close3($color, $red, $green, $blue, $tolerance, $comment)
           Tests if $color's first three channels are within $tolerance of ($red, $green, $blue).

   Test suite functions
       Functions that perform one or more tests, typically used to test various parts of Imager's
       implementation.

       image_bounds_checks($im)
           Attempts to write to various pixel positions outside the edge of the image to ensure that it fails in
           those locations.

           Any new image type should pass these tests.  Does 16 separate tests.

       mask_tests($im, $epsilon)
           Perform a standard set of mask tests on the OO image $im.  Does 24 separate tests.

       diff_text_with_nul($test_name, $text1, $text2, @options)
           Creates 2 test images and writes $text1 to the first image and $text2 to the second image with the
           string() method.  Each call adds 3 "ok"/"not ok" to the output of the test script.

           Extra options that should be supplied include the font and either a color or channel parameter.

           This was explicitly created for regression tests on #21770.

       std_font_tests({ font => $font })
           Perform standard font interface tests.

       std_font_test_count()
           The number of tests performed by std_font_tests().

   Helper functions
       test_image_raw()
           Returns a 150x150x3 Imager::ImgRaw test image.

       test_image()
           Returns a 150x150x3 8-bit/sample OO test image. Name: "basic".

       test_image_16()
           Returns a 150x150x3 16-bit/sample OO test image. Name: "basic16"

       test_image_double()
           Returns a 150x150x3 double/sample OO test image. Name: "basic_double".

       test_image_gray()
           Returns a 150x150 single channel OO test image. Name: "gray".

       test_image_gray_16()
           Returns a 150x150 16-bit/sample single channel OO test image. Name: "gray16".

       test_image_mono()
           Returns a 150x150 bilevel image that passes the is_bilevel() test.  Name: "mono".

       test_image_named($name)
           Return one of the other test images above based on name.

       color_cmp($c1, $c2)
           Performs an ordering of 3-channel colors (like <=>).

       colorf_cmp($c1, $c2)
           Performs an ordering of 3-channel floating point colors (like <=>).

AUTHOR

       Tony Cook <tony@develop-help.com>