[英]Scaling Image with Java produces black space
我編寫了以下功能來按比例縮小圖像。 但是,在進行縮放時,生成的圖像始終是正方形圖像,並且在圖像的底部或右側具有黑色空間。 我在這里做錯了什么?
private BufferedImage scaleImageTo(BufferedImage image, int width, int height) throws Exception {
// Fetch the width and height of the source image, ...
int srcWidth = image.getWidth();
int srcHeight = image.getHeight();
// ... verify that it is larger than the target image ...
if (srcWidth < width && srcHeight < height) {
throw new Exception();
}
// ... and setup the target image with the same dimensions.
BufferedImage scaledImage;
if (image.getType() == BufferedImage.TYPE_CUSTOM) {
scaledImage = new BufferedImage(width,height,BufferedImage.TYPE_3BYTE_BGR);
} else {
scaledImage = new BufferedImage(width, height, image.getType());
}
// Calculate the scale parameter.
double scale = 1;
if (srcWidth - width >= srcHeight - height) {
scale = ((double) width) / srcWidth;
} else {
scale = ((double) height) / srcHeight;
}
// Setup the scaling transformation ...
AffineTransform at = new AffineTransform();
at.scale(scale, scale);
// ... and the transformation interpolation type.
AffineTransformOp scaleOp = new AffineTransformOp(at, AffineTransformOp.TYPE_BILINEAR);
// Generate the scaled image ...
scaledImage = scaleOp.filter(image, scaledImage);
// ... and return it.
return scaledImage;
}
您始終在x方向和y方向上使用相同的比例因子。
盡管您可以通過指定兩個比例因子來解決此問題
double scaleX = (double) width / srcWidth;
double scaleY = (double) height / srcHeight;
AffineTransform at = new AffineTransform();
at.scale(scaleX, scaleY);
我不知道你為什么這樣做。 僅創建圖像的縮放版本通常很容易...:
private static BufferedImage scaleImageTo(
BufferedImage image, int width, int height)
{
BufferedImage scaledImage =
new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = scaledImage.createGraphics();
g.setRenderingHint(
RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g.drawImage(image, 0, 0, width, height, null);
g.dispose();
return scaledImage;
}
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