internal void Read(GifReader reader)
{
Byte size = reader.ReadByte();
if (size != 4)
{
System.Diagnostics.Debug.WriteLine("Wrong size of " + ToString());
}
Byte flags = reader.ReadByte();
disposalMethod = (GifDisposalMethod)((flags & 0x1C) >> 2);
userInputExpected = 0x02 == (flags & 0x02);
transparency = 0x01 == (flags & 0x01);
delay = reader.ReadUInt16();
transparencyIndex = reader.ReadByte();
Byte terminator = reader.ReadByte();
if (terminator != 0x00)
{
throw new Exception("Unknown extension terminator: 0x" + terminator.ToString("X2"));
}
}
/// <summary>
/// Clears canvas colors and resets it to initial state
/// </summary>
public void Reset()
{
frameDisposalMethod = GifDisposalMethod.Keep;
frameX = 0;
frameY = 0;
frameWidth = canvasWidth;
frameHeight = canvasHeight;
if (!canvasIsEmpty)
{
FillWithColor(0, 0, canvasWidth, canvasHeight, new Color32(BackgroundColor.r, BackgroundColor.g, BackgroundColor.b, 0));
canvasIsEmpty = true;
}
}
/// <summary>
/// Method initiates new drawing, sequential calls to OutputPixel will draw everything on canvas
/// </summary>
/// <param name="x">Left offset of frame</param>
/// <param name="y">Top offset of frame</param>
/// <param name="width">Frame width</param>
/// <param name="height">Frame height</param>
/// <param name="palette">Color palette for this frame</param>
/// <param name="transparentColorIndex">Index of transparent color, color from this index will be treated as transparent</param>
/// <param name="isInterlaced">Apply deinterlacing during drawing</param>
/// <param name="disposalMethod">Specifies, how to handle this frame when next frame is drawn</param>
public void BeginNewFrame(int x, int y, int width, int height, Color32[] palette,
int transparentColorIndex, bool isInterlaced, GifDisposalMethod disposalMethod)
{
switch (frameDisposalMethod)
{
case GifDisposalMethod.ClearToBackgroundColor:
FillWithColor(frameX, frameY, frameWidth, frameHeight,
new Color32(BackgroundColor.r, BackgroundColor.g, BackgroundColor.b, 0));
break;
case GifDisposalMethod.Revert:
if (disposalMethod != GifDisposalMethod.Keep)
{
Array.Copy(revertDisposalBuffer, 0, canvasColors, 0, revertDisposalBuffer.Length);
}
break;
}
switch (disposalMethod)
{
case GifDisposalMethod.Revert:
if (revertDisposalBuffer == null)
{
revertDisposalBuffer = new Color32[canvasColors.Length];
}
Array.Copy(canvasColors, 0,
revertDisposalBuffer, 0, revertDisposalBuffer.Length);
break;
}
framePalette = palette;
frameDisposalMethod = disposalMethod;
canvasIsEmpty = false;
frameWidth = width;
frameHeight = height;
frameX = x;
frameY = y;
// Start before canvas, so next pixel output will load correct region
frameCanvasPosition = 0;
frameRowCurrent = -1;
frameCanvasRowEndPosition = -1;
frameTransparentColorIndex = transparentColorIndex;
RouteFrameDrawing(x, y, width, height, isInterlaced);
}
public void ConstructorImageFrameMetadata()
{
const int frameDelay = 42;
const int colorTableLength = 128;
const GifDisposalMethod disposalMethod = GifDisposalMethod.RestoreToBackground;
var metaData = new ImageFrameMetadata();
GifFrameMetadata gifFrameMetadata = metaData.GetGifMetadata();
gifFrameMetadata.FrameDelay = frameDelay;
gifFrameMetadata.ColorTableLength = colorTableLength;
gifFrameMetadata.DisposalMethod = disposalMethod;
var clone = new ImageFrameMetadata(metaData);
GifFrameMetadata cloneGifFrameMetadata = clone.GetGifMetadata();
Assert.Equal(frameDelay, cloneGifFrameMetadata.FrameDelay);
Assert.Equal(colorTableLength, cloneGifFrameMetadata.ColorTableLength);
Assert.Equal(disposalMethod, cloneGifFrameMetadata.DisposalMethod);
}
internal void Read(GifReader reader)
{
Byte size = reader.ReadByte();
if (size != 4)
{
System.Diagnostics.Debug.WriteLine("Wrong size of " + ToString());
}
Byte flags = reader.ReadByte();
disposalMethod = (GifDisposalMethod)((flags & 0x1C) >> 2);
userInputExpected = 0x02 == (flags & 0x02);
transparency = 0x01 == (flags & 0x01);
delay = reader.ReadUInt16();
transparencyIndex = reader.ReadByte();
Byte terminator = reader.ReadByte();
if (terminator != 0x00)
{
throw new Exception("Unknown extension terminator: 0x" + terminator.ToString("X2"));
}
}
public static GifDisposalMethod Clamp(this GifDisposalMethod m) => m <GifDisposalMethod.Preserve || m> GifDisposalMethod.RestorePrevious ? GifDisposalMethod.Preserve : m;
private void DecodeLzwImageToCanvas(int lzwMinCodeSize, int x, int y, int width, int height,
Color32[] colorTable, int transparentColorIndex, bool isInterlaced, GifDisposalMethod disposalMethod)
{
if (header.hasGlobalColorTable)
{
canvas.BackgroundColor = globalColorTable[header.transparentColorIndex];
}
canvas.BeginNewFrame(x, y, width, height, colorTable, transparentColorIndex, isInterlaced, disposalMethod);
lzwDictionary.InitWithWordSize(lzwMinCodeSize);
blockReader.StartNewReading();
lzwDictionary.DecodeStream(blockReader, canvas);
blockReader.FinishReading();
}
