gd 相关问题

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 $image; } 此外，如果您有其他建议来改进此代码，我们将不胜感激！我认为这适用于整个 Opencart 社区，因为这个问题已经讨论过很多次了，但目前还没有发布可行的解决方案。 quality参数仅适用于.jpeg图像。要锐化图像，您可以在 imageconvolution() 函数中应用 resize() 代码。 public function resize($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：使用 PHP gd 库提高图像质量 http://adamhopkinson.co.uk/blog/2010/08/26/sharpen-an-image-using-php-and-gd/

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