(Advanced) php image processing functions and Code examples

Returns an array with four units. Index 0 contains the pixel value of the image width, and index 1 contains the pixel value of the image height. I. create image resources

Imagecreatetruecolor (width, height); imagecreatefromgif (image name); Watermark (image name); imagecreatefromjpeg (image name); draw various image imagegif (image resource, storage path); imagepng () imagejpeg ();

II. retrieving image attributes
Imagesx (res // width
Imagesy (res // height
Getimagesize (file path)
Returns an array with four units. Index 0 contains the pixel value of the image width, and index 1 contains the pixel value of the image height. Index 2 is the mark of the image type: 1 = GIF, 2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF (intel byte order), 8 = TIFF (motorola byte order), 9 = JPC, 10 = JP2, 11 = JPX, 12 = JB2, 13 = SWC, 14 = IFF, 15 = WBMP, 16 = XBM. These tags correspond to the newly added IMAGETYPE constant in PHP 4.3.0. Index 3 is a text string with the content "height =" yyy "width =" xxx "and can be directly used for IMG marking.
Destroy Image resources
Imagedestroy (image resources );

3. transparent processing
PNG and jpeg transparent colors are normal, only gif is abnormal

Imagecolortransparent (resource image [, int color]) // set a color to transparent imagecolorstotal () imagecolorforindex ();

IV. image cropping

imagecopyresized()imagecopyresampled();

5. add watermarks (text and images)
String Encoding and conversion string iconv (string $ in_charset, string $ out_charset, string $ str)

VI. rotating images
Imagerotate (); // specifies the Image flip angle

VII. Image flip
Flip along x axis along y axis

8. sharpen

imagecolorsforindex()imagecolorat()

Image $ img = imagecreatefromgif ("./images/map.gif ");

The code is as follows:

 

Normal image scaling
The code is as follows:
 
$ Filename = ". /images/hee.jpg "; $ per = 0.3; list ($ width, $ height) = getimagesize ($ filename); $ n_w = $ width * $ per; $ n_h = $ width * $ per; $ new = imagecreatetruecolor ($ n_w, $ n_h); $ img = imagecreatefromjpeg ($ filename ); // Copy some images and adjust imagecopyresized ($ new, $ img, 0, 0, $ n_w, $ n_h, $ width, $ height ); // output a new image and save it as imagejpeg ($ new ,". /images/hee2.jpg "); imagedestroy ($ new); imagedestroy ($ img );
Proportional scaling of images, not processing transparent colors
The code is as follows:
 
Function thumn ($ background, $ width, $ height, $ newfile) {list ($ s_w, $ s_h) = getimagesize ($ background ); // Obtain the height and width of the original image. if ($ width & ($ s_w <$ s_h) {$ width = ($ height/$ s_h) * $ s_w ;} else {$ height = ($ width/$ s_w) * $ s_h;} $ new = imagecreatetruecolor ($ width, $ height); $ img = imagecreatefromjpeg ($ background ); imagecopyresampled ($ new, $ img, 0, 0, 0, $ width, $ height, $ s_w, $ s_h); imagejpeg ($ new, $ newfile ); imagedestroy ($ new); imagedestroy ($ img);} thumn ("images/hee.jpg", 200,200 ,". /images/hee3.jpg ");
Gif transparent color processing
The code is as follows:
 
Function thumn ($ background, $ width, $ height, $ newfile) {list ($ s_w, $ s_h) = getimagesize ($ background ); if ($ width & ($ s_w <$ s_h) {$ width = ($ height/$ s_h) * $ s_w ;} else {$ height = ($ width/$ s_w) * $ s_h;} $ new = imagecreatetruecolor ($ width, $ height); $ img = imagecreatefromgif ($ background ); $ otsc = imagecolortransparent ($ img); if ($ otsc >=0 & $ otst <imagecolorstotal ($ img )) {// Determine the index color $ tran = imagecolorsforindex ($ img, $ otsc); // The Index color value $ newt = imagecolorallocate ($ new, $ tran ["red"], $ tran ["green"], $ tran ["blue"]); imagefill ($ new, 0, 0, $ newt); imagecolortransparent ($ new, $ newt );} imagecopyresized ($ new, $ img, 0, 0, 0, 0, $ width, $ height, $ s_w, $ s_h); imagegif ($ new, $ newfile ); imagedestroy ($ new); imagedestroy ($ img);} thumn ("images/map.gif", 200,200 ,". /images/map3.gif ");

Crop Images
The code is as follows:
  

Add text watermarks to images
The code is as follows:
  

Image Rotation
The code is as follows:
  

Horizontal flip vertical flip
The code is as follows:
  
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