(PHP 4, PHP 5)
imagecopyresized — Copy and resize part of an image
$dst_image
, resource $src_image
, int $dst_x
, int $dst_y
, int $src_x
, int $src_y
, int $dst_w
, int $dst_h
, int $src_w
, int $src_h
)
imagecopyresized() copies a rectangular
portion of one image to another image.
dst_image
is the destination image,
src_image
is the source image identifier.
In other words, imagecopyresized() will take an
rectangular area from src_image
of width
src_w
and height src_h
at
position (src_x
,src_y
)
and place it in a rectangular area of dst_image
of width dst_w
and height dst_h
at position (dst_x
,dst_y
).
If the source and destination coordinates and width and heights
differ, appropriate stretching or shrinking of the image fragment
will be performed. The coordinates refer to the upper left
corner. This function can be used to copy regions within the
same image (if dst_image
is the same as
src_image
) but if the regions overlap the
results will be unpredictable.
dst_image
Destination image link resource.
src_image
Source image link resource.
dst_x
x-coordinate of destination point.
dst_y
y-coordinate of destination point.
src_x
x-coordinate of source point.
src_y
y-coordinate of source point.
dst_w
Destination width.
dst_h
Destination height.
src_w
Source width.
src_h
Source height.
Returns TRUE
on success or FALSE
on failure.
Example #1 Resizing an image
This example will display the image at half size.
<?php
// File and new size
$filename = 'test.jpg';
$percent = 0.5;
// Content type
header('Content-Type: image/jpeg');
// Get new sizes
list($width, $height) = getimagesize($filename);
$newwidth = $width * $percent;
$newheight = $height * $percent;
// Load
$thumb = imagecreatetruecolor($newwidth, $newheight);
$source = imagecreatefromjpeg($filename);
// Resize
imagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
// Output
imagejpeg($thumb);
?>
The above example will output something similar to:
The image will be output at half size, though better quality could be obtained using imagecopyresampled().
Note:
There is a problem due to palette image limitations (255+1 colors). Resampling or filtering an image commonly needs more colors than 255, a kind of approximation is used to calculate the new resampled pixel and its color. With a palette image we try to allocate a new color, if that failed, we choose the closest (in theory) computed color. This is not always the closest visual color. That may produce a weird result, like blank (or visually blank) images. To skip this problem, please use a truecolor image as a destination image, such as one created by imagecreatetruecolor().
imagecopyresampled() - Copy and resize part of an image with resampling