function imagerotate(&$srcImg, $angle, $bgcolor, $ignore_transparent = 0)
{
function rotateX($x, $y, $theta)
{
return $x * cos($theta) - $y * sin($theta);
}
function rotateY($x, $y, $theta)
{
return $x * sin($theta) + $y * cos($theta);
}
$srcw = imagesx($srcImg);
$srch = imagesy($srcImg);
if ($angle == 0) {
return $srcImg;
}
// Convert the angle to radians
$theta = deg2rad($angle);
// Calculate the width of the destination image.
$temp = array(rotateX(0, 0, 0 - $theta), rotateX($srcw, 0, 0 - $theta), rotateX(0, $srch, 0 - $theta), rotateX($srcw, $srch, 0 - $theta));
$minX = floor(min($temp));
$maxX = ceil(max($temp));
$width = $maxX - $minX;
// Calculate the height of the destination image.
$temp = array(rotateY(0, 0, 0 - $theta), rotateY($srcw, 0, 0 - $theta), rotateY(0, $srch, 0 - $theta), rotateY($srcw, $srch, 0 - $theta));
$minY = floor(min($temp));
$maxY = ceil(max($temp));
$height = $maxY - $minY;
$destimg = imagecreatetruecolor($width, $height);
imagefill($destimg, 0, 0, imagecolorallocate($destimg, 0, 255, 0));
// sets all pixels in the new image
for ($x = $minX; $x < $maxX; $x++) {
for ($y = $minY; $y < $maxY; $y++) {
// fetch corresponding pixel from the source image
$srcX = round(rotateX($x, $y, $theta));
$srcY = round(rotateY($x, $y, $theta));
if ($srcX >= 0 && $srcX < $srcw && $srcY >= 0 && $srcY < $srch) {
$color = imagecolorat($srcImg, $srcX, $srcY);
} else {
$color = $bgcolor;
}
imagesetpixel($destimg, $x - $minX, $y - $minY, $color);
}
}
return $destimg;
}
/**
* imagerotate() does not appear in PHP with non-bundled GD libraries.
* Because this is written in PHP, it is much slower than the bundled version.
*
* @param resource $srcImg an image resource
* @param float $angle rotation angle, in degrees
* @param int $bgColor specifies the color of the uncovered zone after the rotation
* @param int $ignoreTransparent if set and non-zero, transparent colors are ignored. Default: 0.
* @return resource image resource for the rotated image
* @access private
*/
private function imagerotate($srcImg, $angle, $bgColor, $ignoreTransparent = 0)
{
function rotateX($x, $y, $theta)
{
return $x * cos($theta) - $y * sin($theta);
}
function rotateY($x, $y, $theta)
{
return $x * sin($theta) + $y * cos($theta);
}
$srcW = imagesx($srcImg);
$srcH = imagesy($srcImg);
// Normalize angle
$angle %= 360;
if ($angle == 0) {
if ($ignoreTransparent == 0) {
imagesavealpha($srcImg, true);
}
return $srcImg;
}
// Convert the angle to radians
$theta = deg2rad($angle);
$minX = $maxX = $minY = $maxY = 0;
// Standard case of rotate
if (abs($angle) == 90 || abs($angle) == 270) {
$width = $srcH;
$height = $srcW;
if ($angle == 90 || $angle == -270) {
$minX = 0;
$maxX = $width;
$minY = -$height + 1;
$maxY = 1;
} else {
if ($angle == -90 || $angle == 270) {
$minX = -$width + 1;
$maxX = 1;
$minY = 0;
$maxY = $height;
}
}
} else {
if (abs($angle) === 180) {
$width = $srcW;
$height = $srcH;
$minX = -$width + 1;
$maxX = 1;
$minY = -$height + 1;
$maxY = 1;
} else {
// Calculate the width of the destination image
$temp = array(rotateX(0, 0, 0 - $theta), rotateX($srcW, 0, 0 - $theta), rotateX(0, $srcH, 0 - $theta), rotateX($srcW, $srcH, 0 - $theta));
$minX = floor(min($temp));
$maxX = ceil(max($temp));
$width = $maxX - $minX;
// Calculate the height of the destination image
$temp = array(rotateY(0, 0, 0 - $theta), rotateY($srcW, 0, 0 - $theta), rotateY(0, $srcH, 0 - $theta), rotateY($srcW, $srcH, 0 - $theta));
$minY = floor(min($temp));
$maxY = ceil(max($temp));
$height = $maxY - $minY;
}
}
$destImg = imagecreatetruecolor($width, $height);
if ($ignoreTransparent == 0) {
imagefill($destImg, 0, 0, imagecolorallocatealpha($destImg, 255, 255, 255, 127));
imagesavealpha($destImg, true);
}
// Sets all pixels in the new image
for ($x = $minX; $x < $maxX; $x++) {
for ($y = $minY; $y < $maxY; $y++) {
// Fetch corresponding pixel from the source image
$srcX = round(rotateX($x, $y, $theta));
$srcY = round(rotateY($x, $y, $theta));
if ($srcX >= 0 && $srcX < $srcW && $srcY >= 0 && $srcY < $srcH) {
$color = imagecolorat($srcImg, $srcX, $srcY);
} else {
$color = $bgColor;
}
imagesetpixel($destImg, $x - $minX, $y - $minY, $color);
}
}
return $destImg;
}
