php三角形图案,PHP GD从图片剪切三角形

角形图案,PHP GD从图片剪切三角形"/>

php三角形图案,PHP GD从图片剪切三角形

我确信x / y计算可以用这个更优化，但是它可以用于从给定图像生成具有顶部/右/底部/左三角形的png，并将它们输出为具有透明背景的png -

// Set which triangle to generate

// top, right, bottom or left

$triangle = 'top';

// Load source image

$src = imagecreatefromjpeg ('Desert.jpg');

// Get image width/height

$srcWidth = imagesx ($src);

$srcHeight = imagesy ($src);

// Get centre position

$centreX = floor ($srcWidth / 2);

$centreY = floor ($srcHeight / 2);

// Set new image size and start x/y

switch ($triangle)

{

case 'top':

$destWidth = $srcWidth;

$destHeight = $centreY;

$destSX = 0;

$destSY = 0;

break;

case 'right':

$destWidth = $centreX;

$destHeight = $srcHeight;

$destSX = $centreX;

$destSY = 0;

break;

case 'bottom':

$destWidth = $srcWidth;

$destHeight = $centreY;

$destSX = 0;

$destSY = $centreY;

break;

case 'left':

$destWidth = $centreX;

$destHeight = $srcHeight;

$destSX = 0;

$destSY = 0;

break;

}

// Create the image

$dest = imagecreatetruecolor ($destWidth, $destHeight);

// Copy from source

imagecopy ($dest, $src, 0, 0, $destSX, $destSY, $destWidth, $destHeight);

// OK... we now have the correctly sized rectangle copied over from the source image

// Lets cut it down and turn it into the triangle we want by removing the other triangles

// We remove the area by defining another colour as transparent and creating shapes with that colour

$colRed = imagecolorallocatealpha ($dest, 255, 0, 0, 0);

imagecolortransparent ($dest, $colRed);

switch ($triangle)

{

case 'top':

imagefilledpolygon ($dest, array ($centreX, $destHeight, 0, 0, 0, $destHeight), 3, $colRed);

imagefilledpolygon ($dest, array ($centreX, $destHeight, $destWidth, 0, $destWidth, $destHeight), 3, $colRed);

break;

case 'right':

imagefilledpolygon ($dest, array (0, $centreY, 0, 0, $destWidth, 0), 3, $colRed);

imagefilledpolygon ($dest, array (0, $centreY, 0, $destHeight, $destWidth, $destHeight), 3, $colRed);

break;

case 'bottom':

imagefilledpolygon ($dest, array ($centreX, 0, 0, 0, 0, $destHeight), 3, $colRed);

imagefilledpolygon ($dest, array ($centreX, 0, $destWidth, 0, $destWidth, $destHeight), 3, $colRed);

break;

case 'left':

imagefilledpolygon ($dest, array ($destWidth, $centreY, 0, 0, $destWidth, 0), 3, $colRed);

imagefilledpolygon ($dest, array ($destWidth, $centreY, 0, $destHeight, $destWidth, $destHeight), 3, $colRed);

break;

}

// Output new image

header ('Content-Type: image/png');

imagepng ($dest);

// Clean up

imagedestroy ($src);

imagedestroy ($dest);