我正在为网站构建一个简单的图像裁剪实用程序。
我遇到了一个小问题:每次我这样做都会出现失真(例如,我的选择坐标是粗略估计的,因此以错误的尺寸绘制图像)。
我画这个是为了让你明白我的意思:
这里有一些代码可以帮助您实现我想要实现的目标:
//Get the new coordinates to crop the image.
$x1 = $request->getPost('x1');
$y1 = $request->getPost('y1');
$x2 = $request->getPost('x2');
$y2 = $request->getPost('y2');
$w = $request->getPost('w');
$h = $request->getPost('h');
$croptool_width = $request->getPost('croptool_width');
$croptool_height = $request->getPost('croptool_height');
$original_width = $request->getPost('original_width');
$original_height = $request->getPost('original_height');
$infos = pathinfo($original_image_location);
$extension = strtolower($infos['extension']);
switch($extension) {
case 'gif':
$sourceImage = imagecreatefromgif($original_image_location);
break;
case 'jpg':
case 'jpeg':
$sourceImage = imagecreatefromjpeg($original_image_location);
break;
case 'png':
$sourceImage = imagecreatefrompng($original_image_location);
break;
}
// Take croptool's dimension, transpose selection coordinates to fit the original image.
$scale_y = $original_height / $croptool_height;
$scale_x = $original_width / $croptool_width;
$scaled_x1 = $x1 * $scale_x;
$scaled_y1 = $y1 * $scale_y;
$scaled_x2 = $x2 * $scale_x;
$scaled_y2 = $y2 * $scale_y;
// Crop selection and save to disk
$cropImage = imagecreatetruecolor(Model_Wineries::getCoverImageWidth(), Model_Wineries::getCoverImageHeight());
imagecopyresampled(
$cropImage, $sourceImage,
0, 0,
$scaled_x1, $scaled_y1,
Model_Wineries::getLogoImageWidth(), Model_Wineries::getLogoImageHeight(),
$scaled_x2, $scaled_y2
);
if (file_exists($cover_image_location))
unlink($cover_image_location);
imagejpeg($cropImage, $cover_image_location, 90);
chmod($cover_image_location, 0777);
if (file_exists($original_image_location))
unlink($original_image_location);
我无法弄清楚的部分是如何正确计算 $scale
变量。
$croptool_width 和 $croptool_height 都是缩小后的尺寸。 $original_... 是原始的。
有人能帮帮我吗?
编辑:建议的回复很好,但由于某种原因,所做的任何事情都完全错误,请看这里:
编辑:(代码已更新)
谢谢!
最佳答案
可能是我理解错了,但我认为你计算的是“比例”而不是“比例”。比例尺是原始尺寸与新尺寸的乘积。可能是:
$scale_y = $original_height / $croptool_height;
$scale_x = $original_width / $croptool_width;
$scaled_x1 = $x1 * $scale_x;
$scaled_y1 = $y1 * $scale_y;
$scaled_x2 = $x2 * $scale_x;
$scaled_y2 = $y2 * $scale_y;
//Original height = 1000 and Croptool height = 100 ==> scale_y = 10; Pixel (0, 45) on crop space == 45 * 10 == 450 on original image.
//Original height = 100 and Croptool height = 1000 ==> scale_y = 0.10; Pixel (0, 450) on crop space == 450 * 0.10 == 45 on original image.
希望这对您有所帮助。
编辑:
我不熟悉PHP API,但看起来提供的源宽度和源高度是错误的,也许你可以计算为
imagecopyresampled(
$cropImage, $sourceImage,
0, 0,
$scaled_x1, $scaled_y1,
Model_Wineries::getLogoImageWidth(), Model_Wineries::getLogoImageHeight(),
$scaled_x2 - $scaled_x1, $scaled_y2 - $scaled_y1
);
关于php - 从缩小图像转换选择坐标,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18622958/