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From msahy...@apache.org
Subject [2/2] pdfbox-docs git commit: PDFBOX-3330: add information about text antialiasing for rendering
Date Sun, 11 Dec 2016 09:04:56 GMT
PDFBOX-3330: add information about text antialiasing for rendering


Project: http://git-wip-us.apache.org/repos/asf/pdfbox-docs/repo
Commit: http://git-wip-us.apache.org/repos/asf/pdfbox-docs/commit/f03ca583
Tree: http://git-wip-us.apache.org/repos/asf/pdfbox-docs/tree/f03ca583
Diff: http://git-wip-us.apache.org/repos/asf/pdfbox-docs/diff/f03ca583

Branch: refs/heads/master
Commit: f03ca583e4645ba5a08c63d9edfb73005fba5f22
Parents: 7e9ff66
Author: Maruan Sahyoun <sahyoun@fileaffairs.de>
Authored: Sun Dec 11 10:04:38 2016 +0100
Committer: Maruan Sahyoun <sahyoun@fileaffairs.de>
Committed: Sun Dec 11 10:04:38 2016 +0100

----------------------------------------------------------------------
 content/2.0/faq.md | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/pdfbox-docs/blob/f03ca583/content/2.0/faq.md
----------------------------------------------------------------------
diff --git a/content/2.0/faq.md b/content/2.0/faq.md
index f1a9739..4fce7b0 100644
--- a/content/2.0/faq.md
+++ b/content/2.0/faq.md
@@ -47,7 +47,8 @@ title:   Frequently Asked Questions (FAQ)
 
 ### PDF rendering
 
- - [A drop shadow is missing or at the wrong position when rendering a page](#dropshadow)
 
+ - [A drop shadow is missing or at the wrong position when rendering a page](#dropshadow)
+ - [Why are some texts in poor quality and not antialiased?](#textantialias)
 
 ## General Questions
 
@@ -131,7 +132,7 @@ Make sure that you closed your content stream before saving.
 <a name="textorder"></a>
 
 
-## Why does the extracted text appear in the wrong sequence?
+### Why does the extracted text appear in the wrong sequence?
 
 By default, text extraction is done in the same sequence as the text in the PDF page content
stream.
 PDF is a graphic format, not a text format, and unlike HTML, it has no requirements that
text one on page
@@ -197,4 +198,14 @@ the word "Hello" is drawn.
 
 ### A drop shadow is missing or at the wrong position when rendering a page
 
-Please attach your file in the [PDFBOX-3000](https://issues.apache.org/jira/browse/PDFBOX-3000)
issue
+Please attach your file in the [PDFBOX-3000](https://issues.apache.org/jira/browse/PDFBOX-3000)
issue.
+
+<a name="textantialias"></a>
+
+### Why are some texts in poor quality and not antialiased?
+
+This is because in some PDFs (e.g. the one in PDFBOX-2814 <https://issues.apache.org/jira/browse/PDFBOX-2814>),
text is not
+rendered directly, but as a shaped clipping from a background. Java graphics does not support
"soft clipping"
+<https://bugs.openjdk.java.net/browse/JDK-4212743>, and because of that, the edges
are not looking smooth.
+Soft clipping could be achieved with some extra steps <https://community.oracle.com/blogs/campbell/2006/07/19/java-2d-trickery-soft-clipping>,
+but these would cost additional time and memory space. You can have a higher quality by rendering
at a higher dpi and then downscale the image.


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