Some test text!
To traverse the list of changes in the graphics state.
gs_itr = reader.GetChangesIterator while gs_itr.HasNext do case gs_itr.Current when GState::E_transform # Get transform matrix for this element. Unlike path.GetCTM # that return full transformation matrix gs.GetTransform return # only the transformation matrix that was installed for this element. # # gs.GetTransform when GState::E_line_width # gs.GetLineWidth when GState::E_line_cap # gs.GetLineCap when GState::E_line_join # gs.GetLineJoin when GState::E_miter_limit # gs.GetMiterLimit when GState::E_dash_pattern # dashes = gs.GetDashes # gs.GetPhase end gs_itr.Next end
PDF Data Extraction (Images, Text, Paths)
Full code sample which illustrates how to extract data, do color conversion, image normalization, and how to process changes in the graphics state.
After reading an Element using
ElementReader.Next(), it is possible to access all graphical attributes of the Element through its graphics state. Some applications are more interested in changes in the graphics state than attribute values. For example, a transition from one Element to another may not involve changes in the graphics state. Or, perhaps, there may be changes only to a couple of attributes. In these cases, it isn't efficient to make memberwise comparisons between the old and current graphics states.
To make this easier and more efficient, PDFTron SDK offers an API to enumerate the list of changes between subsequent Elements.
It's also possible to query ElementReader for changes to a specific attribute:
if (reader.IsChanged(GState::E_line_width)) # line width was changed. end
Note that the list of modified attributes is accumulated when calling
ElementReader.Next(). To clear the list of modified attributes use
ElementReader.ClearChangeList() method. A call to
ClearChangeList() serves as a marker in the display list from which further changes in the graphics state are tracked.
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