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Higher-level PHP constructs for manipulating image files (contd.)

Higher-level PHP constructs for manipulating image files (contd.). A library of tools for manipulating images. So far, we have seen the following GD functions imageCreateTrueColor create a new true colour image imageGIF export image in GIF format imagecolorallocate

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Higher-level PHP constructs for manipulating image files (contd.)

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  1. Higher-level PHP constructs for manipulating image files (contd.)

  2. A library of tools for manipulating images • So far, we have seen the following GD functions • imageCreateTrueColor • create a new true colour image • imageGIF • export image in GIF format • imagecolorallocate • add a new colour to the palette for an image • imagefilledrectangle • add a filled rectangle to an image • imagefill • flood fill part of an image • imagefilledellipse • add a filled circle or ellipse to an image • imagefilledpolygon • add a filled polygon to an image

  3. More functions for exporting images • We are not restricted to exporting images in the GIF format • As well as imageGIF, the GD library provides • imagePNG • export image in PNG format • Example usage: imagePNG($image,"someFile.png"); • imagejpeg • export image in JPG format • Example usage: imageJPEG($image,"someFile.jpg");

  4. Functions for drawing unfilled shapes • We are not restricted to drawing filled shapes • As well as imagefilledrectangle, the GD library provides imagerectangle • draws an unfilled rectangle • Example usage: imagerectangle($image, 50, 50, 150, 150, $someColour); • Note that this does not allow us to specify the thickness of the border of the rectangle • By default, the thickness is 1 pixel, but we can change this • imagesetthickness • set the thickness for lines in subsequent drawing in the image • Example usage: imagesetthickness($image, 3);

  5. Drawing a thick-bordered unfilled rectangle

  6. Functions for drawing unfilled shapes (contd.) • Similarly, there is imageellipse • Example usage: imageellipse($image, $cx, $cy, $width, $height, $colour); • imagepolygon • Example usage: imagepolygon($image, $arrayOfPoints, $numPoints, $colour); • imageline • Example usage: imageline($image, $x1, $y1, $x2, $y2, $colour); • imagearc • Draws an arc from a circle or ellipse of some width and height • 0 degrees is at 3 o’clock and arc is drawn clockwise • Example usage: imageline($image, $cx, $cy, $ellipseWidth,$ellipseHeight, $startAngle,$endAngle, $colour);

  7. Drawing a smiley face

  8. Drawing a smiley face <?php $im = imageCreateTrueColor(200, 200); $white = imagecolorallocate($im, 255, 255, 255); $red = imagecolorallocate($im, 255, 0, 0); $green = imagecolorallocate($im, 0, 255, 0); $blue = imagecolorallocate($im, 0, 0, 255); $yellow = imagecolorallocate($im, 255, 255, 0); imagefill($im,1,1,$white); // draw filled circle for head imagefilledellipse($im, 100, 100, 200, 200, $yellow); imagesetthickness($im,4); // draw the mouth imagearc($im, 100, 100, 150, 150, 25, 155, $red); // draw left eye and then the right eye imagearc($im, 60, 75, 50, 50, 0, 360, $green); imagearc($im, 140, 75, 50, 50, 0, 360, $blue); imageGIF($im,"head.gif"); ?>

  9. Creating our own style of line • imagestyle takes two arguments imagestyle($image, $arrayOfPixelColours); • To use our newly defined style of line in subsequent drawing statements, we must use the special identified IMG_COLOR_STYLED instead of a colour name

  10. Using a thick line of our own style

  11. Adding text to an image • imagestring takes six arguments imagestring($image, $font, $x, $y, $string, $colour); • The font can be 1, 2, 3, 4, 5, where higher numbers produce bigger characters

  12. We can also import images and then edit them • imagecreatefromgif • Example usages: $im=imagecreatefromgif("someImage.gif"); $im=imagecreatefromgif("someUrlPointingToAGifFile"); • Similarly, there is • imagecreatefrompng • imagecreatefromjpeg

  13. Drawing on an existing image

  14. Making animations with PHP

  15. Making an animation with PHP <?php include "GIFEncoder.class.php"; if ($dh = opendir ( "frames/" ) ) { while (false !== ( $dat = readdir ( $dh ) ) ) { if ($dat != "." && $dat != ".." ) {$frames [ ] = "frames/$dat"; $framed [ ] = 5; } } closedir ( $dh ); } $gif = new GIFEncoder($frames,$framed,0,2,0,0,0,"url"); fwrite ( fopen( "myanimation.gif","wb"), $gif->GetAnimation()); ?>

  16. Making an animation with PHP <?php include "GIFEncoder.class.php"; /* Build a frames array from sources... */ if ($dh = opendir ( "frames/" ) ) { while (false !== ( $dat = readdir ( $dh ) ) ) { if ($dat != "." && $dat != ".." ) {$frames [ ] = "frames/$dat"; $framed [ ] = 5; } } closedir ( $dh ); } /* GIFEncoder constructor: image_stream = new GIFEncoder (URL or Binary data 'Sources' int 'Delay times' int 'Animation loops' int 'Disposal' int 'Transparent red, green, blue colors' int 'Source type'); */ $gif = new GIFEncoder($frames,$framed,0,2,0,0,0,"url"); fwrite ( fopen( "myanimation.gif","wb"), $gif->GetAnimation()); ?>

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