It's definitively java and not PDFBox; I first did tests whether there
are different rendering hints, but no. Even when not using antialiasing,
there are differences in size. When using it there are differences in
size but also in color count.
Try this code that contains no PDFBox:
int height = 3508;
int width = 2480;
BufferedImage bimg = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = (Graphics2D) bimg.getGraphics();
g.setColor(Color.WHITE);
g.fillRect(0, 0, width, height);
g.setColor(Color.BLACK);
RenderingHints r = new RenderingHints(null);
//r.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
r.put(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.setRenderingHints(r);
int fontSize = 50;
int vertMargin = 200;
int leftMargin = 160;
int eachOffset = fontSize * 3 / 2;
Font f = new Font("Courier New", Font.BOLD, fontSize);
g.setFont(f);
int count = 1;
String text = "123456789 123456789 123456789 123456789 123456789
123456789 ";
while (vertMargin + (eachOffset * (count - 1)) < height - vertMargin)
{
String line = String.format("Line %2d: %s", count, text);
g.drawChars(line.toCharArray(), 0, line.length(), leftMargin,
vertMargin + eachOffset * (count - 1));
++count;
}
g.dispose();
Iterator<ImageWriter> imageWriters =
ImageIO.getImageWritersByFormatName("png");
ImageWriter writer = imageWriters.next();
ImageWriteParam param = writer.getDefaultWriteParam();
if (param.canWriteCompressed())
{
param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
param.setCompressionQuality(0); // best
}
try (ImageOutputStream ios = ImageIO.createImageOutputStream(new
File("test-" + System.getProperty("java.version") + ".png")))
{
writer.setOutput(ios);
writer.write(null, new IIOImage(bimg, null, null), param);
}
writer.dispose();
Tilman
Am 23.04.2021 um 05:55 schrieb Tilman Hausherr:
Yes, I can confirm this. I tried with two versions of amazon corretto,
saving as PNG at 100 dpi.
I need to do more tests with different PDF types to find out why/when
that happens. The two PNG files have a different color count. Because
PNG is non lossy it means that the higher color count exists before
saving.
Tilman
Am 23.04.2021 um 01:24 schrieb Ethan Huang:
Hi Tilman,
Thanks for the suggestion! I have tried with the version 2.0.23. I think
the behavior is the same for different PDFBox versions.
For sharing the file, would this Google Drive link work?
https://drive.google.com/file/d/1Yizkg97z-xyHk9zQj9y9iqhCXr6PfN2S/view?usp=sharing
I think there are some changes made in JDK 11 that are different from
JDK
8, and the parts are used by PDFBox to render images from PDFs.
It would be great if you can point out anything relevant for us to
understand the cause.
On Wed, Apr 21, 2021 at 7:40 PM Tilman Hausherr <[email protected]>
wrote:
Please upload the files to a sharehoster. Also make sure you're using
2.0.23.
Tilman
Am 21.04.2021 um 23:44 schrieb Ethan Huang:
Hello community,
When testing with JDK 11, we found it produces larger file size than
JDK 8 for rendering PDF pages to images. I know PDFBOX uses the
java.awt library to do the rendering but would like to learn more if
we know why it produces such a difference and if it is configurable.
I have attached a test doc we have but I believe this is common to all
docs.
JDK 8
The size of the image produced from the first page: 74137 bytes
The size of the image produced from the second page: 51874 bytes
JDK 11
The size of the image produced from the first page: 102464 bytes
The size of the image produced from the second page: 69454 bytes
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