DynaPDF Manual - Page 584

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Function Reference
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Flag
Description
pfDecomprAllImages
If set, all images are decompressed. Decompressing all images can
be useful if the images should be stored in a specific file format like
TIFF, PNG, or BMP.
If the flag is absent, images which are already stored in a valid file
format are returned as is. This can be useful if no conversion to a
specific image format is required. Images which can be stored
unchanged are Gray and RGB JPEG images, as well as JPEG 2000
compressed images.
pfNoJPXDecode
Meaningful only if the flag pfDecomprAllImages is set. If set, JPEG
2000 images are not decompressed.
pfDitherImagesToBW
This flag is considered only if an image is decompressed. If set,
decompressed images are converted to 1 bit black and white with
the Floyd-Steinberg dithering algorithm. 1 bit images are returned
unchanged.
pfConvImagesToGray
This flag is considered only if an image is decompressed. If set,
decompressed images are converted to gray.
pfConvImagesToRGB
This flag is considered only if an image is decompressed. If set,
decompressed images are converted RGB.
pfConvImagesToCMYK
This flag is considered only if an image is decompressed. If set,
decompressed images are converted CMYK.
pfImageInfoOnly
If set, images are not decompressed. This flag can be useful if no
further processing is required, e.g. if images should be enumerated.
Although the TDrawShading callback function is defined there is no way to process shadings at this
time. Shadings can only be rastered to an image to get a meaningful result. However, such a feature
is not available yet.
The content parser is not part of the Visual Basic interface due to the bad support for callback
functions. Preferred programming languages are C/C++, C#, Delphi, or VB .Net. These
programming languages offer optimal execution speed and the usage is relatively simple. Although
.Net languages support no pointers the execution speed is almost identically to C/C++ or Delphi.
The Graphics State
An application that uses the content parser must maintain an internal graphics state stack that stores
the current graphics state in a LIFO (last in first out) data structure. Depending on what kind of
information should be extracted only a few members of the graphics state maybe required. For
example, an application that extracts text from a PDF file can ignore path painting parameters like
the current line cap style, line width and so on.
 

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