# Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

`GD_VERSION` (string)
  The GD version PHP was compiled against. (Available as of PHP 5.2.4)
`GD_MAJOR_VERSION` (integer)
  The GD major version PHP was compiled against. (Available as of PHP 5.2.4)
`GD_MINOR_VERSION` (integer)
  The GD minor version PHP was compiled against. (Available as of PHP 5.2.4)
`GD_RELEASE_VERSION` (integer)
  The GD release version PHP was compiled against. (Available as of PHP 5.2.4)
`GD_EXTRA_VERSION` (string)
  The GD "extra" version (beta/rc..) PHP was compiled against. (Available as of PHP 5.2.4)
`GD_BUNDLED` (integer)
  When the bundled version of GD is used this is 1 otherwise its set to 0.
`IMG_BMP` (integer)
  Used as a return value by imagetypes()
`IMG_GIF` (integer)
  Used as a return value by imagetypes()
`IMG_JPG` (integer)
  Used as a return value by imagetypes()
`IMG_JPEG` (integer)
  Used as a return value by imagetypes()

  > Note:

  > This constant has the same value as `IMG_JPG`

`IMG_PNG` (integer)
  Used as a return value by imagetypes()
`IMG_WBMP` (integer)
  Used as a return value by imagetypes()
`IMG_XPM` (integer)
  Used as a return value by imagetypes()
`IMG_WEBP` (integer)
  Used as a return value by imagetypes() Available as of PHP 5.6.25 and PHP 7.0.10, respectively.
`IMG_COLOR_TILED` (integer)
  Special color option which can be used instead of a color allocated with imagecolorallocate() or imagecolorallocatealpha().
`IMG_COLOR_STYLED` (integer)
  Special color option which can be used instead of a color allocated with imagecolorallocate() or imagecolorallocatealpha().
`IMG_COLOR_BRUSHED` (integer)
  Special color option which can be used instead of a color allocated with imagecolorallocate() or imagecolorallocatealpha().
`IMG_COLOR_STYLEDBRUSHED` (integer)
  Special color option which can be used instead of a color allocated with imagecolorallocate() or imagecolorallocatealpha().
`IMG_COLOR_TRANSPARENT` (integer)
  Special color option which can be used instead of a color allocated with imagecolorallocate() or imagecolorallocatealpha().
`IMG_AFFINE_TRANSLATE` (integer)
  An affine transformation type constant used by the imageaffinematrixget() function.
`IMG_AFFINE_SCALE` (integer)
  An affine transformation type constant used by the imageaffinematrixget() function.
`IMG_AFFINE_ROTATE` (integer)
  An affine transformation type constant used by the imageaffinematrixget() function.
`IMG_AFFINE_SHEAR_HORIZONTAL` (integer)
  An affine transformation type constant used by the imageaffinematrixget() function.
`IMG_AFFINE_SHEAR_VERTICAL` (integer)
  An affine transformation type constant used by the imageaffinematrixget() function.
`IMG_ARC_ROUNDED` (integer)
  A style constant used by the imagefilledarc() function.

  > Note:

  > This constant has the same value as `IMG_ARC_PIE`

`IMG_ARC_PIE` (integer)
  A style constant used by the imagefilledarc() function.
`IMG_ARC_CHORD` (integer)
  A style constant used by the imagefilledarc() function.
`IMG_ARC_NOFILL` (integer)
  A style constant used by the imagefilledarc() function.
`IMG_ARC_EDGED` (integer)
  A style constant used by the imagefilledarc() function.
`IMG_GD2_RAW` (integer)
  A type constant used by the imagegd2() function.
`IMG_GD2_COMPRESSED` (integer)
  A type constant used by the imagegd2() function.
`IMG_EFFECT_REPLACE` (integer)
  Alpha blending effect used by the imagelayereffect() function.
`IMG_EFFECT_ALPHABLEND` (integer)
  Alpha blending effect used by the imagelayereffect() function.
`IMG_EFFECT_NORMAL` (integer)
  Alpha blending effect used by the imagelayereffect() function.
`IMG_EFFECT_OVERLAY` (integer)
  Alpha blending effect used by the imagelayereffect() function.
`IMG_EFFECT_MULTIPLY` (integer)
  Alpha blending effect used by the imagelayereffect() function.
`IMG_FILTER_NEGATE` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_GRAYSCALE` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_BRIGHTNESS` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_CONTRAST` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_COLORIZE` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_EDGEDETECT` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_GAUSSIAN_BLUR` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_SELECTIVE_BLUR` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_EMBOSS` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_MEAN_REMOVAL` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_SMOOTH` (integer)
  Special GD filter used by the imagefilter() function.
`IMG_FILTER_PIXELATE` (integer)
  Special GD filter used by the imagefilter() function. (Available as of PHP 5.3.0)
`IMG_FILTER_SCATTER` (integer)
  Special GD filter used by the imagefilter() function. (Available as of PHP 7.4.0)
`IMAGETYPE_GIF` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_JPEG` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_JPEG2000` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_PNG` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_SWF` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_PSD` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_BMP` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_WBMP` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_XBM` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_TIFF_II` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_TIFF_MM` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_IFF` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_JB2` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_JPC` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_JP2` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_JPX` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_SWC` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions.
`IMAGETYPE_ICO` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions. (Available as of PHP 5.3.0)
`IMAGETYPE_WEBP` (integer)
  Image type constant used by the image_type_to_mime_type() and image_type_to_extension() functions. (Available as of PHP 7.1.0)
`PNG_NO_FILTER` (integer)
  A special PNG filter, used by the imagepng() function.
`PNG_FILTER_NONE` (integer)
  A special PNG filter, used by the imagepng() function.
`PNG_FILTER_SUB` (integer)
  A special PNG filter, used by the imagepng() function.
`PNG_FILTER_UP` (integer)
  A special PNG filter, used by the imagepng() function.
`PNG_FILTER_AVG` (integer)
  A special PNG filter, used by the imagepng() function.
`PNG_FILTER_PAETH` (integer)
  A special PNG filter, used by the imagepng() function.
`PNG_ALL_FILTERS` (integer)
  A special PNG filter, used by the imagepng() function.
`IMG_FLIP_VERTICAL` (int)
  Used together with imageflip(), available as of PHP 5.5.0.
`IMG_FLIP_HORIZONTAL` (int)
  Used together with imageflip(), available as of PHP 5.5.0.
`IMG_FLIP_BOTH` (int)
  Used together with imageflip(), available as of PHP 5.5.0.
`IMG_BELL` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_BESSEL` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_BILINEAR_FIXED` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_BICUBIC` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_BICUBIC_FIXED` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_BLACKMAN` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_BOX` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_BSPLINE` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_CATMULLROM` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_GAUSSIAN` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_GENERALIZED_CUBIC` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_HERMITE` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_HAMMING` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_HANNING` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_MITCHELL` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_POWER` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_QUADRATIC` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_SINC` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_NEAREST_NEIGHBOUR` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_WEIGHTED4` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.
`IMG_TRIANGLE` (int)
  Used together with imagesetinterpolation(), available as of PHP 5.5.0.