extmod/modframebuf: Enable blit between different formats via a palette.

This achieves a substantial performance improvement when rendering glyphs
to color displays, the benefit increasing proportional to the number of
pixels in the glyph.

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/extmod/framebuf_palette.py b/tests/extmod/framebuf_palette.py
new file mode 100644
index 000000000..84db834c1
--- /dev/null
+++ b/tests/extmod/framebuf_palette.py
@@ -0,0 +1,35 @@
+# Test blit between different color spaces
+try:
+    import framebuf, usys
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+# Monochrome glyph/icon
+w = 8
+h = 8
+cbuf = bytearray(w * h // 8)
+fbc = framebuf.FrameBuffer(cbuf, w, h, framebuf.MONO_HLSB)
+fbc.line(0, 0, 7, 7, 1)
+
+# RGB565 destination
+wd = 16
+hd = 16
+dest = bytearray(wd * hd * 2)
+fbd = framebuf.FrameBuffer(dest, wd, hd, framebuf.RGB565)
+
+wp = 2
+bg = 0x1234
+fg = 0xF800
+pal = bytearray(wp * 2)
+palette = framebuf.FrameBuffer(pal, wp, 1, framebuf.RGB565)
+palette.pixel(0, 0, bg)
+palette.pixel(1, 0, fg)
+
+fbd.blit(fbc, 0, 0, -1, palette)
+
+print(fbd.pixel(0, 0) == fg)
+print(fbd.pixel(7, 7) == fg)
+print(fbd.pixel(8, 8) == 0)  # Ouside blit
+print(fbd.pixel(0, 1) == bg)
+print(fbd.pixel(1, 0) == bg)