nuttx-apps/tools/README.txt
Gregory Nutt dee7f14b49 Squashed commit of the following:
apps/system/nxplayer:  Fix some logical errors from recent comments.  They broke the build of the nxplayer as a library vs. a task.  apps/graphics/nxglyphs:  Fix yet more namespace problems.

    graphics/nxwm/src/nxwm_main.cxx:  Move from graphics/nxwidgets/UnitTests/nxwm/nxwm_main.cxx.

    apps/graphicx/nx*:  Fixes numerous build issues mostly associated with include paths and namespaces.

    apps/nxglyphs:  Decouple (mostly) from nxwidgets and nxwm so that they can be used elsewhere.  Creates include/graphics/nxglyphs.h

    apps/graphics/nxglyphs:  Put all NxWidgets and NxWM glyphs into a common directory where they can eventually be shared.  Not very sharable at the moment due to header file entanglements.  Need a separate nxglyps.hxx header file.

    Separate nxwidets and nxwm into separate directories.  Remove old, common NxWidgets directory.
2019-04-04 18:53:29 -06:00

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NxWidgets/tools README File
===========================
bitmap_converter.py
-------------------
This script converts from any image type supported by Python imaging library to
the RLE-encoded format used by NxWidgets.
RLE (Run Length Length) is a very simply encoding that compress quite well
with certain kinds of images: Images that that have many pixels of the
same color adjacent on a row (like simple graphics). It does not work well
with photographic images.
But even simple graphics may not encode compactly if, for example, they have
been resized. Resizing an image can create hundreds of unique colors that
may differ by only a bit or two in the RGB representation. This "color
smear" is the result of pixel interpolation (and might be eliminated if
your graphics software supports resizing via pixel replication instead of
interpolation).
When a simple graphics image does not encode well, the symptom is that
the resulting RLE data structures are quite large. The pallette structure,
in particular, may have hundreds of colors in it. There is a way to fix
the graphic image in this case. Here is what I do (in fact, I do this
on all images prior to conversion just to be certain):
- Open the original image in GIMP.
- Select the option to select the number of colors in the image.
- Pick the smallest number of colors that will represent the image
faithfully. For most simple graphic images this might be as few as 6
or 8 colors.
- Save the image as PNG or other lossless format (NOT jpeg).
- Then generate the image.