include/vcl/bitmap/BitmapFilter.hxx | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
New commits:
commit 3b4793b366982d84b07fefe26470d0d12bf49733
Author: Christopher Sherlock <chris.sherloc...@gmail.com>
AuthorDate: Tue Jan 28 18:58:14 2025 +1100
Commit: Tomaž Vajngerl <qui...@gmail.com>
CommitDate: Fri Feb 14 12:38:15 2025 +0100
vcl: document BitmapFilter
Change-Id: I68cbb0a6b9050c89050afd1906d6fd948f9bff45
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/180822
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <qui...@gmail.com>
diff --git a/include/vcl/bitmap/BitmapFilter.hxx
b/include/vcl/bitmap/BitmapFilter.hxx
index f6a57cd46646..496d562bee19 100644
--- a/include/vcl/bitmap/BitmapFilter.hxx
+++ b/include/vcl/bitmap/BitmapFilter.hxx
@@ -42,6 +42,28 @@ void generateStripRanges(
} // end vcl::bitmap
+/** BitmapFilter transforms (or "filters") a given bitmap based on a provided
filter.
+ It is based on the command pattern, which allows for additional filters
without
+ needing to modify existing client code.
+
+ The BitmapFilter class is the base class, to implement a new filter you
derive
+ your new filter from this and implement the filtering functionality in the
execute()
+ function.
+
+ The execute function takes the bitmapex that you want to apply the filter
to, and
+ returns a brand new, filtered, BitmapEx instance.
+
+ The actual filters parameterisation is expected to be done in the
constructor. So, to
+ take a simple example, if you want to make every fourth pixel a different
color you
+ would accept a BitmapColor parameter that specifies the color, and stores
this as a
+ member variable that the Bitmap4thColorReplaceFilter would then use in
it's execute()
+ statement.
+
+ The BitmapFilter class has a static convenience Filter function that takes
a BitmapEx
+ and the desired filter, which filters the BitmapEx parameter, then
overwrite this BitmapEx
+ instance. If the filter fails (BitmapEx is empty) then it returns false.
+*/
+
class VCL_DLLPUBLIC BitmapFilter
{
public:
