imageviewer: gif viewer based on giflib-5.0.2

This adds ability to view gif images in rockbox.
Works both on color and gray/monochrome targets (greylib).
Aspect correction is supported as well.

Limitations:
- animated gifs are restricted to 32 frames
- animated gifs loop always (loopcount is ignored)
- plain text extension is not supported
- animated gifs with interframe delay = 0 are treated as still
  images (web browsers usually treat delay 0 as 100ms to prevent
  exhaustive CPU load by such images)

Change-Id: I61501f801ddcd403410e38d83e6bddc9883e7ede

1 files changed, 30 insertions, 0 deletions

diff --git a/apps/plugins/imageviewer/gif/gif.make b/apps/plugins/imageviewer/gif/gif.make
new file mode 100644
index 0000000000..8260524ffe
--- /dev/null
+++ b/apps/plugins/imageviewer/gif/gif.make
@@ -0,0 +1,30 @@
+#             __________               __   ___.
+#   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+#   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+#   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+#   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+#                     \/            \/     \/    \/            \/
+# $Id$
+#
+
+GIFSRCDIR := $(IMGVSRCDIR)/gif
+GIFBUILDDIR := $(IMGVBUILDDIR)/gif
+
+GIF_SRC := $(call preprocess, $(GIFSRCDIR)/SOURCES)
+GIF_OBJ := $(call c2obj, $(GIF_SRC))
+
+OTHER_SRC += $(GIF_SRC)
+
+ROCKS += $(GIFBUILDDIR)/gif.ovl
+
+$(GIFBUILDDIR)/gif.refmap: $(GIF_OBJ)
+$(GIFBUILDDIR)/gif.link: $(PLUGIN_LDS) $(GIFBUILDDIR)/gif.refmap
+$(GIFBUILDDIR)/gif.ovl: $(GIF_OBJ)
+
+#-Os breaks decoder - dunno why
+GIFFLAGS = $(IMGDECFLAGS) -O0
+
+# Compile PNG plugin with extra flags (adapted from ZXBox)
+$(GIFBUILDDIR)/%.o: $(GIFSRCDIR)/%.c $(GIFSRCDIR)/gif.make
+        $(SILENT)mkdir -p $(dir $@)
+        $(call PRINTS,CC $(subst $(ROOTDIR)/,,$<))$(CC) -I$(dir $<) $(GIFFLAGS) -c $< -o $@