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@@ -1016,6 +1016,46 @@ Can I control this?</question> |
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</p> |
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</answer> |
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</faq> |
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<faq id="acrobat-anti-aliasing"> |
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<question>How can I get rid of strange single-pixel lines inside table borders or between table cells in Adobe Acrobat?</question> |
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<answer> |
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<p> |
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Since Apache FOP supports the collapsed border model, every border segment consists |
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of two separate shapes. This is due to the fact that each side of the border |
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segment can have a different color. Now, Adobe Acrobat may display thin (1 pixel wide) |
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lines inside the border segment or sometimes even between to adjacent |
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colored rectangles making up the background of a block or table cell. |
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This effect is due to the way Adobe Acrobat does anti-aliasing. Adobe's algorithm |
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seems to cause these artifacts. Other PDF viewers don't have that problem. Or at least |
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we haven't had any reports in that direction. |
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</p> |
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<p> |
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First of all, these artifacts do not appear in print since no anti-aliasing is done |
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by Adobe Acrobat in this case (except maybe if you tell Acrobat to print the page |
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as a bitmap in which case Adobe fully composes the page itself). So, if the artifacts appear |
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on screen, it doesn't mean they have to appear in print, too. |
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</p> |
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<p> |
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To get rid of the artifacts, you can call up the "Preferences" dialog of |
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Adobe Acrobat and select the tab "Page display". Enabling "Enhance thin lines" |
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may help in some situations. Otherwise, you can disable "Smooth line art". |
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You may have to disable "Use 2D graphics acceleration", too, so you can disable |
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"Smooth line art" in the first place. |
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</p> |
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<p> |
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Here an example of how the effect can look like (left: anti-aliasing on, right: anti-aliasing off): |
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</p> |
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<figure src="images/acrobat-anti-aliasing-artifacts.png" alt="Left: anti-aliasing on, Right: off"/> |
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<p> |
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Unfortunately, it is not possible to control the above settings from within the PDF file. |
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The user has to change these settings himself. Improving FOP to avoid this kind of problem |
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would be possible although rather hard to achieve because we'd need to add a considerable |
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amount of code to combine the various line segments. Something like that has been tried already |
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years ago showing that this is a tricky task. Also, the improvement may not justify the amount |
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of effort required. |
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</p> |
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</answer> |
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</faq> |
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</part> |
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<part id="part-iex"> |
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<title>IEx specific stuff</title> |