我在 Opencart 中进行 GD 图像处理时遇到了这个问题，它在调整大小后会创建非常糟糕的模糊图像。到目前为止我所尝试的一切都没有帮助。 下面是 image.php 的代码
<?php
class Image {
private $file;
private $image;
private $info;
public function __construct($file) {
if (file_exists($file)) {
$this->file = $file;
$info = getimagesize($file);
$this->info = array(
'width' => $info[0],
'height' => $info[1],
'bits' => $info['bits'],
'mime' => $info['mime']
);
$this->image = $this->create($file);
} else {
exit('Error: Could not load image ' . $file . '!');
}
}
private function create($image) {
$mime = $this->info['mime'];
if ($mime == 'image/gif') {
return imagecreatefromgif($image);
} elseif ($mime == 'image/png') {
return imagecreatefrompng($image);
} elseif ($mime == 'image/jpeg') {
return imagecreatefromjpeg($image);
}
}
public function save($file, $quality = 100) {
$info = pathinfo($file);
$extension = strtolower($info['extension']);
if (is_resource($this->image)) {
if ($extension == 'jpeg' || $extension == 'jpg') {
imagejpeg($this->image, $file, $quality);
} elseif($extension == 'png') {
imagepng($this->image, $file);
} elseif($extension == 'gif') {
imagegif($this->image, $file);
}
imagedestroy($this->image);
}
}
/**
*
* @param width
* @param height
* @param default char [default, w, h]
* default = scale with white space,
* w = fill according to width,
* h = fill according to height
*
*/
public function resize($width = 0, $height = 0, $default = '') {
if (!$this->info['width'] || !$this->info['height']) {
return;
}
$xpos = 0;
$ypos = 0;
$scale = 1;
$scale_w = $width / $this->info['width'];
$scale_h = $height / $this->info['height'];
if ($default == 'w') {
$scale = $scale_w;
} elseif ($default == 'h'){
$scale = $scale_h;
} else {
$scale = min($scale_w, $scale_h);
}
if ($scale == 1 && $scale_h == $scale_w && $this->info['mime'] != 'image/png')
{
return;
}
$new_width = (int)($this->info['width'] * $scale);
$new_height = (int)($this->info['height'] * $scale);
$xpos = (int)(($width - $new_width) / 2);
$ypos = (int)(($height - $new_height) / 2);
$image_old = $this->image;
$this->image = imagecreatetruecolor($width, $height);
if (isset($this->info['mime']) && $this->info['mime'] == 'image/png') {
imagealphablending($this->image, false);
imagesavealpha($this->image, true);
$background = imagecolorallocatealpha($this->image, 255, 255, 255, 127);
imagecolortransparent($this->image, $background);
} else {
$background = imagecolorallocate($this->image, 255, 255, 255);
}
imagefilledrectangle($this->image, 0, 0, $width, $height, $background);
imagecopyresampled($this->image, $image_old, $xpos, $ypos, 0, 0, $new_width,
$new_height, $this->info['width'], $this->info['height']);
imagedestroy($image_old);
$this->info['width'] = $width;
$this->info['height'] = $height;
}
public function watermark($file, $position = 'bottomright') {
$watermark = $this->create($file);
$watermark_width = imagesx($watermark);
$watermark_height = imagesy($watermark);
switch($position) {
case 'topleft':
$watermark_pos_x = 0;
$watermark_pos_y = 0;
break;
case 'topright':
$watermark_pos_x = $this->info['width'] - $watermark_width;
$watermark_pos_y = 0;
break;
case 'bottomleft':
$watermark_pos_x = 0;
$watermark_pos_y = $this->info['height'] - $watermark_height;
break;
case 'bottomright':
$watermark_pos_x = $this->info['width'] - $watermark_width;
$watermark_pos_y = $this->info['height'] - $watermark_height;
break;
}
imagecopy($this->image, $watermark,
$watermark_pos_x, $watermark_pos_y, 0, 0, 120, 40);
imagedestroy($watermark);
}
public function crop($top_x, $top_y, $bottom_x, $bottom_y) {
$image_old = $this->image;
$this->image = imagecreatetruecolor($bottom_x - $top_x, $bottom_y - $top_y);
imagecopy($this->image, $image_old, 0, 0, $top_x, $top_y,
$this->info['width'], $this->info['height']);
imagedestroy($image_old);
$this->info['width'] = $bottom_x - $top_x;
$this->info['height'] = $bottom_y - $top_y;
}
public function rotate($degree, $color = 'FFFFFF') {
$rgb = $this->html2rgb($color);
$this->image = imagerotate($this->image, $degree,
imagecolorallocate($this->image, $rgb[0], $rgb[1], $rgb[2]));
$this->info['width'] = imagesx($this->image);
$this->info['height'] = imagesy($this->image);
}
private function filter($filter) {
imagefilter($this->image, $filter);
}
private function text($text, $x = 0, $y = 0, $size = 5, $color = '000000') {
$rgb = $this->html2rgb($color);
imagestring($this->image, $size, $x, $y, $text,
imagecolorallocate($this->image, $rgb[0], $rgb[1], $rgb[2]));
}
private function merge($file, $x = 0, $y = 0, $opacity = 100) {
$merge = $this->create($file);
$merge_width = imagesx($image);
$merge_height = imagesy($image);
imagecopymerge($this->image, $merge, $x, $y, 0, 0, $merge_width,
$merge_height, $opacity);
}
private function html2rgb($color) {
if ($color[0] == '#') {
$color = substr($color, 1);
}
if (strlen($color) == 6) {
list($r, $g, $b) = array($color[0] . $color[1], $color[2] . $color[3],
$color[4] . $color[5]);
} elseif (strlen($color) == 3) {
list($r, $g, $b) = array($color[0] . $color[0], $color[1] . $color[1],
$color[2] . $color[2]);
} else {
return false;
}
$r = hexdec($r);
$g = hexdec($g);
$b = hexdec($b);
return array($r, $g, $b);
}
}
?>
正如您所看到的，质量已经设置为 100 ，所以这没有帮助。 我尝试用 resample 替换 resize - 但这没有产生可见的结果。 然而，我发现了这个建议（下面的代码）来锐化图像，不幸的是我不知道如何以及在哪里使用它。特别是因为原始代码处理多种图像类型。请帮忙把它放在正确的地方。
{
$matrix = array(
array(-1, -1, -1),
array(-1, 16, -1),
array(-1, -1, -1),
);
$divisor = array_sum(array_map('array_sum', $matrix));
$offset = 0;
imageconvolution($image, $matrix, $divisor, $offset);
return $image;
}
此外，如果您有其他建议来改进此代码，我们将不胜感激！我认为这适用于整个 Opencart 社区，因为这个问题已经讨论过很多次了，但目前还没有发布可行的解决方案。
quality.jpegimageconvolution()resize()public function resize($width = 0, $height = 0, $default = '') {
if (!$this->info['width'] || !$this->info['height']) {
return;
}
$xpos = 0;
$ypos = 0;
$scale = 1;
$scale_w = $width / $this->info['width'];
$scale_h = $height / $this->info['height'];
if ($default == 'w') {
$scale = $scale_w;
} elseif ($default == 'h') {
$scale = $scale_h;
} else {
$scale = min($scale_w, $scale_h);
}
if ($scale == 1 && $scale_h == $scale_w && $this->info['mime'] != 'image/png') {
return;
}
$new_width = (int)($this->info['width'] * $scale);
$new_height = (int)($this->info['height'] * $scale);
$xpos = (int)(($width - $new_width) / 2);
$ypos = (int)(($height - $new_height) / 2);
$image_old = $this->image;
$this->image = imagecreatetruecolor($width, $height);
if (isset($this->info['mime']) && $this->info['mime'] == 'image/png') {
imagealphablending($this->image, false);
imagesavealpha($this->image, true);
$background = imagecolorallocatealpha($this->image, 255, 255, 255, 127);
imagecolortransparent($this->image, $background);
} else {
$background = imagecolorallocate($this->image, 255, 255, 255);
}
imagefilledrectangle($this->image, 0, 0, $width, $height, $background);
imagecopyresampled($this->image, $image_old, $xpos, $ypos, 0, 0, $new_width, $new_height, $this->info['width'], $this->info['height']);
//Image Sharpening Code
$matrix = array(
array(0.0, -1.0, 0.0),
array(-1.0, 5.0, -1.0),
array(0.0, -1.0, 0.0)
);
$divisor = array_sum(array_map('array_sum', $matrix));
$offset = 0;
imageconvolution($this->image, $matrix, $divisor, $offset);
// End Image Sharpening Code
imagedestroy($image_old);
$this->info['width'] = $width;
$this->info['height'] = $height;
}
参考资料：