tools: add gfx-convert

gfx-convert is a tool, usually to be run a Linux host PC, that converts
SVG or PNG files into an eraw file. By doing this, EGT can render graphics
faster.

Signed-off-by: Wayne Jia <[email protected]>
[[email protected]: style.sh script fixes]
Tested-by: Ludovic Desroches <[email protected]>

Author: Wayne Jia

tools/gfx-convert/Makefile

@@ -0,0 +1,14 @@
+CXX = g++
+CXXFLAGS = -std=c++17 $(shell pkg-config --cflags libegt) \
+    -I../../src/detail/ -I../../external/cxxopts/include/ \
+    -I../../external/rapidxml/ -Wall
+
+LDFLAGS = $(shell pkg-config --libs libegt)
+
+all: gfx-convert
+
+gfx-convert: gfx-convert.cpp
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) $< -o $@ $(LDFLAGS)
+
+clean:
+	rm -f gfx-convert eraw.*

tools/gfx-convert/README.md

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+# gfx-convert tool
+
+This tool is used to convert SVG or PNG file into eraw.bin which can be loaded
+by EGT code directly to make graphic render fast. Usually this tool is running
+on your Linux host PC, because it has no meaning if you convert graphics on
+embedded target.
+
+## Usage Example
+
+1. Before using this tool, please make sure that you've followed the egt build
+instruction to build egt library ready.
+```
+	git clone --recursive https://github.com/linux4sam/egt.git
+	cd egt
+	./autogen.sh
+	./configure
+	make
+```
+2. Make the gfx-convert tool.
+```
+	cd egt/tool/gfx-convert
+	make
+```
+3. Start the gfx-convert, of course, you can run ./gfx-convert -h to get help.
+
+```
+	./gfx-convert -s
+	./gfx-convert -i png picture1.png
+	./gfx-convert -i png picture2.png
+		......
+	./gfx-convert -i png pictureN.png
+	./gfx-convert file.svg
+	./gfx-convert -e
+```
+4. When conversion finished, copy ./eraw.h to source code to include in your
+application cpp code, and copy ./eraw.bin to the target. At last your application
+will read eraw.bin on target to get the graphics data.
+
+5. The generated eraw.h has an array inidicating the graphics id with offset and
+length, and it has an array index in the comment. So when you are coding, you could
+use the array index directly without iterating the array to find the graphics you
+want. There is an example in egt/examples/motorcycledash.cpp, please refer to that
+to learn how to use the eraw.h and eraw.bin.
+
+## License
+
+EGT is released under the terms of the `Apache 2` license. See the [COPYING](../COPYING)
+file for more information.