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https://issues.apache.org/jira/browse/PDFBOX-2853?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jakob Pyttlik updated PDFBOX-2853:
----------------------------------
Description:
CCITT-Images with colorspace different from PDIndexed are created using
PDCCitt.java/getRGBImage:
{code}
if (colorspace instanceof PDIndexed)
{
...
}
else
{
byte[] map = new byte[] { (byte) 0x00, (byte) 0xFF };
colorModel = new IndexColorModel(1, map.length, map, map, map,
Transparency.OPAQUE);
}
{code}
The value Transparency.OPAQUE (=1) is provided for the parameter
"transparentIndex" - this creates an image, in which the white color is treated
as transparent.
This bug is especially annoying for some OCR-documents I had to work with
(using PageDrawer). They consist of rendered text (as result of the OCR), that
has the original content as image rendered on top, fully covering the text.
When the white background is rendered as transparent, the rendered page gets
messed up, because both texts can be seen,
*Proposed Fix/Patch*
Replace the value *Transparency.OPAQUE* with *-1*, so that no color is
transparent.
was:
CCITT-Images with colorspace different from PDIndexed are created using
getRGBImage
{code}
if (colorspace instanceof PDIndexed)
{
...
}
else
{
byte[] map = new byte[] { (byte) 0x00, (byte) 0xFF };
colorModel = new IndexColorModel(1, map.length, map, map, map,
Transparency.OPAQUE);
}
{code}
The value Transparency.OPAQUE (=1) is provided for the parameter
"transparentIndex" - this creates an image, in which the white color is treated
as transparent.
This bug is especially annoying for some OCR-documents I had to work with
(using PageDrawer). They consist of rendered text (as result of the OCR), that
has the original content as image rendered on top, fully covering the text.
When the white background is rendered as transparent, the rendered page gets
messed up, because both texts can be seen,
*Proposed Fix/Patch*
Replace the value *Transparency.OPAQUE* with *-1*, so that no color is
transparent.
> CCITT: Background is rendered as transparent color
> --------------------------------------------------
>
> Key: PDFBOX-2853
> URL: https://issues.apache.org/jira/browse/PDFBOX-2853
> Project: PDFBox
> Issue Type: Bug
> Components: Rendering
> Affects Versions: 1.8.9
> Reporter: Jakob Pyttlik
> Labels: easyfix
> Attachments: ccittbug.png
>
>
> CCITT-Images with colorspace different from PDIndexed are created using
> PDCCitt.java/getRGBImage:
> {code}
> if (colorspace instanceof PDIndexed)
> {
> ...
> }
> else
> {
> byte[] map = new byte[] { (byte) 0x00, (byte) 0xFF };
> colorModel = new IndexColorModel(1, map.length, map, map, map,
> Transparency.OPAQUE);
> }
> {code}
> The value Transparency.OPAQUE (=1) is provided for the parameter
> "transparentIndex" - this creates an image, in which the white color is
> treated as transparent.
> This bug is especially annoying for some OCR-documents I had to work with
> (using PageDrawer). They consist of rendered text (as result of the OCR),
> that has the original content as image rendered on top, fully covering the
> text. When the white background is rendered as transparent, the rendered page
> gets messed up, because both texts can be seen,
> *Proposed Fix/Patch*
> Replace the value *Transparency.OPAQUE* with *-1*, so that no color is
> transparent.
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