Merge branch 'master' of git://192.168.1.10/home/me/arsd

apng.d

@@ -0,0 +1,237 @@
+/++
+	Support for [animated png|https://wiki.mozilla.org/APNG_Specification] files.
++/
+module arsd.apng;
+
+import arsd.png;
+
+// acTL
+// must be in the file before the IDAT
+struct AnimationControlChunk {
+	uint num_frames;
+	uint num_plays;
+}
+
+// fcTL
+struct FrameControlChunk {
+	align(1):
+	// this should go up each time, for frame control AND for frame data, each increases.
+	uint sequence_number;
+	uint width;
+	uint height;
+	uint x_offset;
+	uint y_offset;
+	ushort delay_num;
+	ushort delay_den;
+	APNG_DISPOSE_OP dispose_op;
+	APNG_BLEND_OP blend_op;
+
+	static assert(dispose_op.offsetof == 24);
+	static assert(blend_op.offsetof == 25);
+}
+
+// fdAT
+class ApngFrame {
+
+	ApngAnimation parent;
+
+	this(ApngAnimation parent) {
+		this.parent = parent;
+	}
+
+	FrameControlChunk frameControlChunk;
+
+	ubyte[] compressedDatastream;
+
+	ubyte[] data;
+	void populateData() {
+		if(data !is null)
+			return;
+
+		import std.zlib;
+
+		auto raw = cast(ubyte[]) uncompress(compressedDatastream);
+		auto bpp = bytesPerPixel(parent.header);
+
+		auto width = frameControlChunk.width;
+		auto height = frameControlChunk.height;
+
+		auto bytesPerLine = bytesPerLineOfPng(parent.header.depth, parent.header.type, width);
+
+		int idataIdx;
+		ubyte[] idata;
+
+		idata.length = width * height * (parent.header.type == 3 ? 1 : 4);
+
+		ubyte[] previousLine;
+		foreach(y; 0 .. height) {
+			auto filter = raw[0];
+			raw = raw[1 .. $];
+			auto line = raw[0 .. bytesPerLine];
+			raw = raw[bytesPerLine .. $];
+
+			auto unfiltered = unfilter(filter, line, previousLine, bpp);
+			previousLine = line;
+
+			convertPngData(parent.header.type, parent.header.depth, unfiltered, width, idata, idataIdx);
+		}
+
+		this.data = idata;
+	}
+
+	// then need to uncompress it
+	// and unfilter it...
+	// and then convert it to the right format.
+
+	MemoryImage frameData;
+}
+
+class ApngAnimation {
+	PngHeader header;
+	AnimationControlChunk acc;
+	Color[] palette;
+	ApngFrame[] frames;
+	// default image? tho i can just load it as a png for that too.
+
+	MemoryImage render() {
+		return null;
+	}
+}
+
+enum APNG_DISPOSE_OP : byte {
+	NONE = 0,
+	BACKGROUND = 1,
+	PREVIOUS = 2
+}
+
+enum APNG_BLEND_OP : byte {
+	SOURCE = 0,
+	OVER = 1
+}
+
+void readApng(in ubyte[] data) {
+	auto png = readPng(data);
+	auto header = PngHeader.fromChunk(png.chunks[0]);
+	Color[] palette;
+	if(header.type == 3) {
+		palette = fetchPalette(png);
+	}
+
+	auto obj = new ApngAnimation();
+
+	bool seenIdat = false;
+	bool seenFctl = false;
+
+	int frameNumber;
+	int expectedSequenceNumber = 0;
+
+	foreach(chunk; png.chunks) {
+		switch(chunk.stype) {
+			case "IDAT":
+				seenIdat = true;
+				// all I care about here are animation frames,
+				// so if this isn't after a control chunk, I'm
+				// just going to ignore it. Read the file with
+				// readPng if you want that.
+				if(!seenFctl)
+					continue;
+
+				assert(obj.frames[0]);
+
+				obj.frames[0].compressedDatastream ~= chunk.payload;
+			break;
+			case "acTL":
+				AnimationControlChunk c;
+				int offset = 0;
+				c.num_frames |= chunk.payload[offset++] << 24;
+				c.num_frames |= chunk.payload[offset++] << 16;
+				c.num_frames |= chunk.payload[offset++] <<  8;
+				c.num_frames |= chunk.payload[offset++] <<  0;
+
+				c.num_plays |= chunk.payload[offset++] << 24;
+				c.num_plays |= chunk.payload[offset++] << 16;
+				c.num_plays |= chunk.payload[offset++] <<  8;
+				c.num_plays |= chunk.payload[offset++] <<  0;
+
+				assert(offset == chunk.payload.length);
+
+				obj.acc = c;
+				obj.frames = new ApngFrame[](c.num_frames);
+			break;
+			case "fcTL":
+				FrameControlChunk c;
+				int offset = 0;
+
+				seenFctl = true;
+
+				c.sequence_number |= chunk.payload[offset++] << 24;
+				c.sequence_number |= chunk.payload[offset++] << 16;
+				c.sequence_number |= chunk.payload[offset++] <<  8;
+				c.sequence_number |= chunk.payload[offset++] <<  0;
+
+				c.width |= chunk.payload[offset++] << 24;
+				c.width |= chunk.payload[offset++] << 16;
+				c.width |= chunk.payload[offset++] <<  8;
+				c.width |= chunk.payload[offset++] <<  0;
+
+				c.height |= chunk.payload[offset++] << 24;
+				c.height |= chunk.payload[offset++] << 16;
+				c.height |= chunk.payload[offset++] <<  8;
+				c.height |= chunk.payload[offset++] <<  0;
+
+				c.x_offset |= chunk.payload[offset++] << 24;
+				c.x_offset |= chunk.payload[offset++] << 16;
+				c.x_offset |= chunk.payload[offset++] <<  8;
+				c.x_offset |= chunk.payload[offset++] <<  0;
+
+				c.y_offset |= chunk.payload[offset++] << 24;
+				c.y_offset |= chunk.payload[offset++] << 16;
+				c.y_offset |= chunk.payload[offset++] <<  8;
+				c.y_offset |= chunk.payload[offset++] <<  0;
+
+				c.delay_num |= chunk.payload[offset++] <<  8;
+				c.delay_num |= chunk.payload[offset++] <<  0;
+
+				c.delay_den |= chunk.payload[offset++] <<  8;
+				c.delay_den |= chunk.payload[offset++] <<  0;
+
+				c.dispose_op = cast(APNG_DISPOSE_OP) chunk.payload[offset++];
+				c.blend_op = cast(APNG_BLEND_OP) chunk.payload[offset++];
+
+				assert(offset == chunk.payload.length);
+
+				if(expectedSequenceNumber != c.sequence_number)
+					throw new Exception("malformed apng file");
+
+				expectedSequenceNumber++;
+
+
+				if(obj.frames[frameNumber] is null)
+					obj.frames[frameNumber] = new ApngFrame(obj);
+				obj.frames[frameNumber].frameControlChunk = c;
+
+				frameNumber++;
+			break;
+			case "fdAT":
+				uint sequence_number;
+				int offset;
+
+				sequence_number |= chunk.payload[offset++] << 24;
+				sequence_number |= chunk.payload[offset++] << 16;
+				sequence_number |= chunk.payload[offset++] <<  8;
+				sequence_number |= chunk.payload[offset++] <<  0;
+
+				if(expectedSequenceNumber != sequence_number)
+					throw new Exception("malformed apng file");
+
+				expectedSequenceNumber++;
+
+				// and the rest of it is a datastream...
+				obj.frames[frameNumber - 1].compressedDatastream ~= chunk.payload;
+			break;
+			default:
+				// ignore
+		}
+
+	}
+}