问题
EDIT: This can be easily done in CSS, I didn't know CSS much at the time of writing this
I have created a thumbnail creator using PHP. The thumbnails generated should be of the same size. But the problem is the use of uploads images having different aspect ratio like landscape or portrait the thumbnail becomes ugly. So I created the picture above for clarification. Whatever be the uploaded image, it will be put into a rectangle image. So the aspect ratio doesn't change and thumbnails will be of the same size. Can anyone pls help me or tell some ideas?
回答1:
define('THUMBNAIL_IMAGE_MAX_WIDTH', 150);
define('THUMBNAIL_IMAGE_MAX_HEIGHT', 150);
function generate_image_thumbnail($source_image_path, $thumbnail_image_path)
{
list($source_image_width, $source_image_height, $source_image_type) = getimagesize($source_image_path);
switch ($source_image_type) {
case IMAGETYPE_GIF:
$source_gd_image = imagecreatefromgif($source_image_path);
break;
case IMAGETYPE_JPEG:
$source_gd_image = imagecreatefromjpeg($source_image_path);
break;
case IMAGETYPE_PNG:
$source_gd_image = imagecreatefrompng($source_image_path);
break;
}
if ($source_gd_image === false) {
return false;
}
$source_aspect_ratio = $source_image_width / $source_image_height;
$thumbnail_aspect_ratio = THUMBNAIL_IMAGE_MAX_WIDTH / THUMBNAIL_IMAGE_MAX_HEIGHT;
if ($source_image_width <= THUMBNAIL_IMAGE_MAX_WIDTH && $source_image_height <= THUMBNAIL_IMAGE_MAX_HEIGHT) {
$thumbnail_image_width = $source_image_width;
$thumbnail_image_height = $source_image_height;
} elseif ($thumbnail_aspect_ratio > $source_aspect_ratio) {
$thumbnail_image_width = (int) (THUMBNAIL_IMAGE_MAX_HEIGHT * $source_aspect_ratio);
$thumbnail_image_height = THUMBNAIL_IMAGE_MAX_HEIGHT;
} else {
$thumbnail_image_width = THUMBNAIL_IMAGE_MAX_WIDTH;
$thumbnail_image_height = (int) (THUMBNAIL_IMAGE_MAX_WIDTH / $source_aspect_ratio);
}
$thumbnail_gd_image = imagecreatetruecolor($thumbnail_image_width, $thumbnail_image_height);
imagecopyresampled($thumbnail_gd_image, $source_gd_image, 0, 0, 0, 0, $thumbnail_image_width, $thumbnail_image_height, $source_image_width, $source_image_height);
$img_disp = imagecreatetruecolor(THUMBNAIL_IMAGE_MAX_WIDTH,THUMBNAIL_IMAGE_MAX_WIDTH);
$backcolor = imagecolorallocate($img_disp,0,0,0);
imagefill($img_disp,0,0,$backcolor);
imagecopy($img_disp, $thumbnail_gd_image, (imagesx($img_disp)/2)-(imagesx($thumbnail_gd_image)/2), (imagesy($img_disp)/2)-(imagesy($thumbnail_gd_image)/2), 0, 0, imagesx($thumbnail_gd_image), imagesy($thumbnail_gd_image));
imagejpeg($img_disp, $thumbnail_image_path, 90);
imagedestroy($source_gd_image);
imagedestroy($thumbnail_gd_image);
imagedestroy($img_disp);
return true;
}
generate_image_thumbnail('original_image.jpg', 'thumb_image.jpg'); //call the function
with that code, you will get something similar to
回答2:
Look at the source code of my Mr Thumb Image Resizing. :)
public function proportion($max_width, $max_height) {
if (!( $this->halt )) {
if ($this->image['extension'] == 'gif') {
$this->image['ratio'] = ( $this->image['width'] > $this->image['height'] ) ? $max_width / $this->image['width'] : $max_height / $this->image['height'];
if ($this->image['width'] > $max_width || $this->image['height'] > $max_height) {
$new_width = $this->image['width'] * $this->image['ratio'];
$new_height = $this->image['height'] * $this->image['ratio'];
} else {
$new_width = $this->image['width'];
$new_height = $this->image['height'];
}
$this->image['composite'] = imagecreatetruecolor($new_width, $new_height);
imagecopyresampled($this->image['composite'], $this->image['render'], 0, 0, 0, 0, $new_width, $new_height, $this->image['width'], $this->image['height']);
$this->image['colorcount'] = imagecolorstotal($this->image['render']);
imagetruecolortopalette($this->image['composite'], true, $this->image['colorcount']);
imagepalettecopy($this->image['composite'], $this->image['render']);
$this->image['transparentcolor'] = imagecolortransparent($this->image['render']);
imagefill($this->image['composite'], 0, 0, $this->image['transparentcolor']);
imagecolortransparent($this->image['composite'], $this->image['transparentcolor']);
} else {
$this->image['ratio'] = ( $this->image['width'] > $this->image['height'] ) ? $max_width / $this->image['width'] : $max_height / $this->image['height'];
if ($this->image['width'] > $max_width || $this->image['height'] > $max_height) {
$new_width = $this->image['width'] * $this->image['ratio'];
$new_height = $this->image['height'] * $this->image['ratio'];
} else {
$new_width = $this->image['width'];
$new_height = $this->image['height'];
}
$this->image['composite'] = imagecreatetruecolor($new_width, $new_height);
imagecopyresampled($this->image['composite'], $this->image['render'], 0, 0, 0, 0, $new_width, $new_height, $this->image['width'], $this->image['height']);
}
} else {
echo 'Execution halted!';
}
}
回答3:
Here's a function that might help you out. You tell it the width you want to maintain, and it will preserve the aspect ratio while also producing a thumbnail.
public static function makeThumb($src, $dest, $desired_width, $format = 'image/jpeg')
{
/* read the source image */
$source_image = null;
if($format == 'image/jpeg')
{
$source_image = imagecreatefromjpeg($src);
}
else if($format == 'image/png')
{
$source_image = imagecreatefrompng($src);
}
$width = imagesx($source_image);
$height = imagesy($source_image);
/* find the "desired height" of this thumbnail, relative to the desired width */
$desired_height = floor($height * ($desired_width / $width));
/* create a new, "virtual" image */
$virtual_image = imagecreatetruecolor($desired_width, $desired_height);
imageAlphaBlending($virtual_image, false);
imageSaveAlpha($virtual_image, true);
/* copy source image at a resized size */
imagecopyresampled($virtual_image, $source_image, 0, 0, 0, 0, $desired_width, $desired_height, $width, $height);
/* create the physical thumbnail image to its destination */
if($format == 'image/jpeg')
{
imagejpeg($virtual_image, $dest);
}
else if($format == 'image/png')
{
imagepng($virtual_image, $dest);
}
}
回答4:
Use ImageMagick API .Check out this
define('THUMB_WIDTH', 60);
define('THUMB_HEIGHT', 80);
define('MAGICK_PATH','/usr/local/bin/');
function makeThumbnail($in, $out) {
$width = THUMB_WIDTH;
$height = THUMB_HEIGHT;
list($w,$h) = getimagesize($in);
$thumbRatio = $width/$height;
$inRatio = $w/$h;
$isLandscape = $inRatio > $thumbRatio;
$size = ($isLandscape ? '1000x'.$height : $width.'x1000');
$xoff = ($isLandscape ? floor((($inRatio*$height)-$width)/2) : 0);
$command = MAGICK_PATH."convert $in -resize $size -crop {$width}x{$height}+{$xoff}+0 ".
"-colorspace RGB -strip -quality 90 $out";
exec($command);
}
Refer to this link - http://coffeeshopped.com/2009/01/creating-image-thumbnails-using-php-and-imagemagick or http://in1.php.net/manual/en/class.imagick.php
来源：https://stackoverflow.com/questions/23148795/php-create-thumbnail-maintaining-aspect-ratio