PDFBox的:写入HD图像PDF
我想转换形象使用cameraa到A4 PDFPDFBox的:写入HD图像PDF
// Read image width and height float imageWidth = bitmap.getWidth();
float imageHeight = bitmap.getHeight();
// Read page width and height ignoring the margins
float pageWidth = PDRectangle.A4.getWidth() - (margin_left_right * 2);
float pageHeight = PDRectangle.A4.getHeight() - (margin_top_bottom * 2);
Log.d("Image Resize", String.valueOf(imageWidth) + " x " + String.valueOf(imageHeight));
Log.d("Image Resize", String.valueOf(pageWidth) + " x " + String.valueOf(pageHeight));
# Image: 4160.0 x 3120.0
# Page: 575.27563 x 821.8898
Log.d("Image Resize", String.valueOf(requiredRatio));
Log.d("Image Resize", String.valueOf(newImageWidth) + " x " + String.valueOf(newImageHeight));
# Required ratio: 0.13828741
# After scaling: 575 x 431
问题是图像大小为4160 x 3120
出手,得到调整后575 x 431
,看起来非常像素化。
PDF通常如何解决这个问题?在使用contentStream.drawImage()
写作时,有没有办法在600 dpi
处说4160 x 3120
?
这question还支持的事实,如果写不调整大小等于图像的高度和宽度的页面,OP只能看到图像的15%,应该如何是按比例缩小而不会损失质量?
回答:
有一个重载drawImage()
方法来做到这一点
contentStream.drawImage(PDImageXObject, float x, float y) contentStream.drawImage(PDImageXObject, float x, float y, float height, float width)
通过在contentStream.drawImage()
指定明确的宽度和高度,可以做到这一点。例如,如果你想显示的图像更小的4倍,但仍保留了相同的分辨率,它可以使用
scaleDownRatio = 0.25; pageSize = PDRectangle.A4;
# this will draw image at bottom left corner
PDImageXObject pageImageXObject = LosslessFactory.createFromImage(document, bitmap);
contentStream.drawImage(pageImageXObject, 0, 0, bitmap.getWidth() * ratio, bitmap.getHeight() * ratio)
# to center it you can use something like
contentStream.drawImage(pageImageXObject, (pageSize.getWidth() - bitmap.getWidth() * ratio)/2, (pageSize.getHeight() - bitmap.getHeight() * ratio)/2, bitmap.getWidth() * ratio, bitmap.getHeight() * ratio)
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