# Image Processing and GD

- Introduction
- Installing/Configuring
  - Requirements
  - Installation
  - Runtime Configuration
  - Resource Types
- Predefined Constants
- Examples
  - PNG creation with PHP
  - Adding watermarks to images using alpha channels
  - Using imagecopymerge to create a translucent watermark
- GD and Image Functions
  - gd_info — Retrieve information about the currently installed GD library
  - getimagesize — Get the size of an image
  - getimagesizefromstring — Get the size of an image from a string
  - image_type_to_extension — Get file extension for image type
  - image_type_to_mime_type — Get Mime-Type for image-type returned by getimagesize, exif_read_data, exif_thumbnail, exif_imagetype
  - image2wbmp — Output image to browser or file
  - imageaffine — Return an image containing the affine transformed src image, using an optional clipping area
  - imageaffinematrixconcat — Concatenate two affine transformation matrices
  - imageaffinematrixget — Get an affine transformation matrix
  - imagealphablending — Set the blending mode for an image
  - imageantialias — Should antialias functions be used or not
  - imagearc — Draws an arc
  - imagebmp — Output a BMP image to browser or file
  - imagechar — Draw a character horizontally
  - imagecharup — Draw a character vertically
  - imagecolorallocate — Allocate a color for an image
  - imagecolorallocatealpha — Allocate a color for an image
  - imagecolorat — Get the index of the color of a pixel
  - imagecolorclosest — Get the index of the closest color to the specified color
  - imagecolorclosestalpha — Get the index of the closest color to the specified color + alpha
  - imagecolorclosesthwb — Get the index of the color which has the hue, white and blackness
  - imagecolordeallocate — De-allocate a color for an image
  - imagecolorexact — Get the index of the specified color
  - imagecolorexactalpha — Get the index of the specified color + alpha
  - imagecolormatch — Makes the colors of the palette version of an image more closely match the true color version
  - imagecolorresolve — Get the index of the specified color or its closest possible alternative
  - imagecolorresolvealpha — Get the index of the specified color + alpha or its closest possible alternative
  - imagecolorset — Set the color for the specified palette index
  - imagecolorsforindex — Get the colors for an index
  - imagecolorstotal — Find out the number of colors in an image's palette
  - imagecolortransparent — Define a color as transparent
  - imageconvolution — Apply a 3x3 convolution matrix, using coefficient and offset
  - imagecopy — Copy part of an image
  - imagecopymerge — Copy and merge part of an image
  - imagecopymergegray — Copy and merge part of an image with gray scale
  - imagecopyresampled — Copy and resize part of an image with resampling
  - imagecopyresized — Copy and resize part of an image
  - imagecreate — Create a new palette based image
  - imagecreatefrombmp — Create a new image from file or URL
  - imagecreatefromgd2 — Create a new image from GD2 file or URL
  - imagecreatefromgd2part — Create a new image from a given part of GD2 file or URL
  - imagecreatefromgd — Create a new image from GD file or URL
  - imagecreatefromgif — Create a new image from file or URL
  - imagecreatefromjpeg — Create a new image from file or URL
  - imagecreatefrompng — Create a new image from file or URL
  - imagecreatefromstring — Create a new image from the image stream in the string
  - imagecreatefromwbmp — Create a new image from file or URL
  - imagecreatefromwebp — Create a new image from file or URL
  - imagecreatefromxbm — Create a new image from file or URL
  - imagecreatefromxpm — Create a new image from file or URL
  - imagecreatetruecolor — Create a new true color image
  - imagecrop — Crop an image to the given rectangle
  - imagecropauto — Crop an image automatically using one of the available modes
  - imagedashedline — Draw a dashed line
  - imagedestroy — Destroy an image
  - imageellipse — Draw an ellipse
  - imagefill — Flood fill
  - imagefilledarc — Draw a partial arc and fill it
  - imagefilledellipse — Draw a filled ellipse
  - imagefilledpolygon — Draw a filled polygon
  - imagefilledrectangle — Draw a filled rectangle
  - imagefilltoborder — Flood fill to specific color
  - imagefilter — Applies a filter to an image
  - imageflip — Flips an image using a given mode
  - imagefontheight — Get font height
  - imagefontwidth — Get font width
  - imageftbbox — Give the bounding box of a text using fonts via freetype2
  - imagefttext — Write text to the image using fonts using FreeType 2
  - imagegammacorrect — Apply a gamma correction to a GD image
  - imagegd2 — Output GD2 image to browser or file
  - imagegd — Output GD image to browser or file
  - imagegetclip — Get the clipping rectangle
  - imagegif — Output image to browser or file
  - imagegrabscreen — Captures the whole screen
  - imagegrabwindow — Captures a window
  - imageinterlace — Enable or disable interlace
  - imageistruecolor — Finds whether an image is a truecolor image
  - imagejpeg — Output image to browser or file
  - imagelayereffect — Set the alpha blending flag to use layering effects
  - imageline — Draw a line
  - imageloadfont — Load a new font
  - imageopenpolygon — Draws an open polygon
  - imagepalettecopy — Copy the palette from one image to another
  - imagepalettetotruecolor — Converts a palette based image to true color
  - imagepng — Output a PNG image to either the browser or a file
  - imagepolygon — Draws a polygon
  - imagerectangle — Draw a rectangle
  - imageresolution — Get or set the resolution of the image
  - imagerotate — Rotate an image with a given angle
  - imagesavealpha — Whether to retain full alpha channel information when saving PNG images
  - imagescale — Scale an image using the given new width and height
  - imagesetbrush — Set the brush image for line drawing
  - imagesetclip — Set the clipping rectangle
  - imagesetinterpolation — Set the interpolation method
  - imagesetpixel — Set a single pixel
  - imagesetstyle — Set the style for line drawing
  - imagesetthickness — Set the thickness for line drawing
  - imagesettile — Set the tile image for filling
  - imagestring — Draw a string horizontally
  - imagestringup — Draw a string vertically
  - imagesx — Get image width
  - imagesy — Get image height
  - imagetruecolortopalette — Convert a true color image to a palette image
  - imagettfbbox — Give the bounding box of a text using TrueType fonts
  - imagettftext — Write text to the image using TrueType fonts
  - imagetypes — Return the image types supported by this PHP build
  - imagewbmp — Output image to browser or file
  - imagewebp — Output a WebP image to browser or file
  - imagexbm — Output an XBM image to browser or file
  - iptcembed — Embeds binary IPTC data into a JPEG image
  - iptcparse — Parse a binary IPTC block into single tags
  - jpeg2wbmp — Convert JPEG image file to WBMP image file
  - png2wbmp — Convert PNG image file to WBMP image file