DynaPDF Manual - Page 265

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Function Reference
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-> see enum TRenderingIntent (PDF 1.1, default
-> 0.0..1.0 (PDF 1.3, default none)
-> 0.0..1.0 (PDF 1.4, default 1.0)
-> 0 or 1 (PDF 1.4, default 1)
-> true or false, default false
A value that should not be modified must not be changed.
The structure contains many reserved fields which are not used at this time. Future extensions will
replace reserved fields.
If an image should be inserted with transparency it is usually best to disable image transparency
which based on color key masking (see SetUseTransparency()). Images use the fill alpha constant as
alpha channel. Blend modes can be applied too. However, the result of blend modes depends
strongly on the used color space. If the image is not defined in an ICC based color space then the
result depends on the color management settings.
Whenever transparency related settings are changed (FillAlpha, StrokeAlpha, or BlendMode) it is
strongly recommended to attach an ICC profile of the output color space for which the file was
created with AddOutputIntent().
If no output intent was specified, Adobe's Acrobat or Reader simulate a default CMYK color space
as output color space if transparency is used on a page, also if the page uses RGB colors only! This
differs from normal RGB files which use no transparency and causes often unwanted color changes.
Note that this rule applies also to images which contain an alpha channel!
If the PDF file uses RGB colors only, then attach an sRGB profile to the file. Such a profile is very
small but it makes a huge difference whether the profile is present or not.
Transparency and blend modes are discussed in detail in the section PDF Transparency.
Return values:
If the function succeeds the return value is the extended graphics state handle, a value greater or
equal zero. If the function fails the return value is a negative error code.

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