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Posted to dev@pdfbox.apache.org by "Christian Appl (Jira)" <ji...@apache.org> on 2020/07/31 08:34:00 UTC
[jira] [Comment Edited] (PDFBOX-4928) Could the new rendering
method of PageDrawer be optional?
[ https://issues.apache.org/jira/browse/PDFBOX-4928?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17168517#comment-17168517 ]
Christian Appl edited comment on PDFBOX-4928 at 7/31/20, 8:33 AM:
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Sorry, I will try to explain clearer what I meant. Maybe the following code example will help?
{code:java}
File heicPDF = new File("D:\\experiments", "test.pdf");
PDDocument document = PDDocument.load(heicPDF);
try {
Map<RenderingHints.Key, Object> renderOptions = new HashMap<RenderingHints.Key, Object>();
renderOptions.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
renderOptions.put(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
renderOptions.put(RenderingHints.KEY_QUALITY_RENDERING_METHOD, RenderingHints.VALUE_PRESCALE_RENDERING_METHOD);
PDFRenderer pdfRenderer = new PDFRenderer(document);
RenderingHints renderingHints = new RenderingHints(renderOptions);
pdfRenderer.setRenderingHints(renderingHints);
BufferedImage image = pdfRenderer.renderImageWithDPI(1, 500, ImageType.RGB);
ImageIO.write(image, "PNG", new File("D:\\experiments", "out_enabled_500.png"));
} finally {
document.close();
}
{code}
My suggestion is the introduction of an additional rendering parameter for the quality rendering (KEY_QUALITY_RENDERING_METHOD in this example). Instead of (scaleX < 0.5 || {color:#000000}scaleY {color}< 0.5) you could check for: {color:#000000}RenderingHints{color}.{color:#871094}VALUE_PRESCALE_RENDERING_METHOD{color}.equals({color:#871094}graphics{color}.getRenderingHint({color:#000000}RenderingHints{color}.{color:#871094}KEY_QUALITY_RENDERING_METHOD{color})
This would enable the user to directly select whether graphics.drawImage() shall apply the transformation matrix, or the introduced prescaling shall be applied. (to intentionally enable or disable the prescaling.)
was (Author: capsvd):
Sorry, I will try to explain clearer what I meant. Maybe the following code example will help?
{code:java}
File heicPDF = new File("D:\\experiments", "test.pdf");
PDDocument document = PDDocument.load(heicPDF);
try {
Map<RenderingHints.Key, Object> renderOptions = new HashMap<RenderingHints.Key, Object>();
renderOptions.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
renderOptions.put(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
renderOptions.put(RenderingHints.KEY_QUALITY_RENDERING_METHOD, RenderingHints.VALUE_PRESCALE_RENDERING_METHOD);
PDFRenderer pdfRenderer = new PDFRenderer(document);
RenderingHints renderingHints = new RenderingHints(renderOptions);
pdfRenderer.setRenderingHints(renderingHints);
BufferedImage image = pdfRenderer.renderImageWithDPI(1, 500, ImageType.RGB);
ImageIO.write(image, "PNG", new File("D:\\experiments", "out_disabled_500.png"));
} finally {
document.close();
}
{code}
My suggestion is the introduction of an additional rendering parameter for the quality rendering (KEY_QUALITY_RENDERING_METHOD in this example). Instead of (scaleX < 0.5 || {color:#000000}scaleY {color}< 0.5) you could check for: {color:#000000}RenderingHints{color}.{color:#871094}VALUE_PRESCALE_RENDERING_METHOD{color}.equals({color:#871094}graphics{color}.getRenderingHint({color:#000000}RenderingHints{color}.{color:#871094}KEY_QUALITY_RENDERING_METHOD{color})
This would enable the user to directly select whether graphics.drawImage() shall apply the transformation matrix, or the introduced prescaling shall be applied. (to intentionally enable or disable the prescaling.)
> Could the new rendering method of PageDrawer be optional?
> ---------------------------------------------------------
>
> Key: PDFBOX-4928
> URL: https://issues.apache.org/jira/browse/PDFBOX-4928
> Project: PDFBox
> Issue Type: Wish
> Components: Rendering
> Affects Versions: 2.0.20
> Reporter: Christian Appl
> Priority: Major
>
> This relates to {color:#008dde}PDFBOX-4516, PDFBOX-4527, PDFBOX-4815, PDFBOX-4886, PDFBOX-4863{color}{color:#008dde}
> I have tested the new prescaled rendering method for the {color}org.apache.pdfbox.rendering.{color:#008dde}PageDrawer {color:#172b4d}with PDFBox:2.0.21-SNAPSHOT{color}{color} for different images, with different resolutions, target image sizes etc. and compared the results to our old expectations (pre 2.0.20). And I really like it!
>
> However it seems to depend on the person's subjective perception (atleast for my tested images), whether I like the old or the new results better. When asking my colleagues, I heard arguments for both sides.
>
> Therefore my question is: Could a RenderingHint be introduced to disable/enable this separately and more intentionally, instead of assuming, that the scaling method must always be applied for specific scaling factors?
> This would allow users to select the scaling method according to their own liking and needs.
>
> I can not really find a crystal clear, objective answer, whether the one or the other is "better", therefore I would prefer being able to de/activate it according to my own judgement.
> As far as I understand, the criterion (scaleX < {color:#1750eb}0.5 {color}|| {color:#000000}scaleY {color}< {color:#1750eb}0.5{color}) has been selected rather arbitrarily.( ? )
> But what if I want to apply it even to images above those scaling factors?
> What if I want to not apply it to images bellow those scaling factors?
> What if I want to apply it to Image A, but not to Image C, for some unknown reason?
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