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LII. Funzioni per le immagini
Introduzione
In PHP puoi usare delle funzioni specifiche per sapere la dimensione di un'immagine JPEG, GIF, PNG, SWF, TIFF e JPEG2000.
Requisiti
Se hai installato le librerie GD (scaricabili su http://www.boutell.com/gd/) sarai anche in grado di creare immagini al volo e di modificarle.
I formati delle immagini sulle quali potrai agire dipendono dalla versione delle librerie GD che hai installato, e dalle altre librerie di cui GD può aver bisogno per accedere a quei formati di immagine. Versioni precedenti alla gd-1.6 supportano il formato GIF ma non quello PNG, mentre versioni superiori alla gd-1.6 supportano il formato PNG ma non il GIF.
Se hai compilato PHP con l'opzione --enable-exif sarai in grado di lavorare con le informazioni memorizzate negli header delle immagini JPEG e TIFF. Queste funzioni non richiedono le librerie GD.
Installazione
Per leggere e scrivere immagini in formato JPEG avrai bisogno di installare jpeg-6b (scaricabile da ftp://ftp.uu.net/graphics/jpeg/) e quindi ricompilare le librerie GD in modo che usino jpeg-6b. Dovrai anche compilare PHP con l'opzione --with-jpeg-dir=/percorso/per/jpeg-6b.
Per aggiungere il supporto per i Font Type 1 dovrai installare t1lib (scaricabile su ftp://sunsite.unc.edu/pub/Linux/libs/graphics/), e quindi aggiungere l'opzione --with-t1lib[=dir].
Configurazione di Runtime
Questa estensione non definisce alcuna direttiva di configurazione in php.ini
Tipi di risorse
Questa estensione non definisce alcun tipo di risorsa.
Costanti predefinite
Queste costanti sono definite da questa estensione e sono disponibili solo se l'estensione è stata compilata nel PHP o se è stata caricata dinamicamente a runtime.
- IMG_GIF (integer)
- IMG_JPG (integer)
- IMG_JPEG (integer)
- IMG_PNG (integer)
- IMG_WBMP (integer)
- IMG_XPM (integer)
- IMG_COLOR_TILED (integer)
- IMG_COLOR_STYLED (integer)
- IMG_COLOR_BRUSHED (integer)
- IMG_COLOR_STYLEDBRUSHED (integer)
- IMG_COLOR_TRANSPARENT (integer)
- IMG_ARC_ROUNDED (integer)
- IMG_ARC_PIE (integer)
- IMG_ARC_CHORD (integer)
- IMG_ARC_NOFILL (integer)
- IMG_ARC_EDGED (integer)
- IMAGETYPE_GIF (integer)
- IMAGETYPE_JPEG (integer)
- IMAGETYPE_PNG (integer)
- IMAGETYPE_SWF (integer)
- IMAGETYPE_PSD (integer)
- IMAGETYPE_BMP (integer)
- IMAGETYPE_WBMP (integer)
- IMAGETYPE_XBM (integer)
- IMAGETYPE_TIFF_II (integer)
- IMAGETYPE_TIFF_MM (integer)
- IMAGETYPE_IFF (integer)
- IMAGETYPE_JB2 (integer)
- IMAGETYPE_JPC (integer)
- IMAGETYPE_JP2 (integer)
- IMAGETYPE_JPX (integer)
- IMAGETYPE_SWC (integer)
- Sommario
- gd_info -- Retrieve information about the currently installed GD library
- getimagesize -- Get the size of an image
- 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 -- Rende disponibile l'immagine per il browser o la salva in un file
- imagealphablending -- Set the blending mode for an image
- imageantialias -- Should antialias functions be used or not
- imagearc -- Draw a partial ellipse
- 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 nearest to the given color
- 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
- 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
- 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
- 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
- imagedashedline -- Draw a dashed line
- imagedestroy -- Destroy an image
- imageellipse -- Draw an ellipse
- imagefill -- Flood fill
- imagefilledarc -- Draw a partial ellipse 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
- 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
- imagegif -- Output image to browser or file
- 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 the bundled libgd layering effects
- imageline -- Draw a line
- imageloadfont -- Load a new font
- imagepalettecopy -- Copy the palette from one image to another
- imagepng -- Output a PNG image to either the browser or a file
- imagepolygon -- Draw a polygon
- imagepsbbox -- Give the bounding box of a text rectangle using PostScript Type1 fonts
- imagepscopyfont -- Make a copy of an already loaded font for further modification
- imagepsencodefont -- Change the character encoding vector of a font
- imagepsextendfont -- Extend or condense a font
- imagepsfreefont -- Free memory used by a PostScript Type 1 font
- imagepsloadfont -- Load a PostScript Type 1 font from file
- imagepsslantfont -- Slant a font
- imagepstext -- To draw a text string over an image using PostScript Type1 fonts
- imagerectangle -- Draw a rectangle
- imagerotate -- Rotate an image with a given angle
- imagesavealpha -- Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images
- imagesetbrush -- Set the brush image for line drawing
- 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
- imagexbm -- Output XBM image to browser or file
- iptcembed -- Embed binary IPTC data into a JPEG image
- iptcparse -- Parse a binary IPTC http://www.iptc.org/ block into single tags.
- jpeg2wbmp -- Convert JPEG image file to WBMP image file
- png2wbmp -- Convert PNG image file to WBMP image file
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Generated: 2007-01-26 17:56:37