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Add support for top right and bottom right image origin

pull/1574/head
Brian Popow 6 years ago
parent
9fece40328
commit
ae1480c0c2
2 changed files with 205 additions and 62 deletions
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  1. 239
      src/ImageSharp/Formats/Tga/TgaDecoderCore.cs
  2. 28
      src/ImageSharp/Formats/Tga/TgaImageOrigin.cs

239
src/ImageSharp/Formats/Tga/TgaDecoderCore.cs
View File

@ -17,6 +17,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// </summary>
internal sealed class TgaDecoderCore
{
/// <summary>
/// A scratch buffer to reduce allocations.
/// </summary>
private readonly byte[] buffer = new byte[4];
/// <summary>
/// The metadata.
/// </summary>
@ -88,7 +93,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
{
try
{
bool inverted = this.ReadFileHeader(stream);
TgaImageOrigin origin = this.ReadFileHeader(stream);
this.currentStream.Skip(this.fileHeader.IdLength);
// Parse the color map, if present.
@ -131,7 +136,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
pixels,
palette.Array,
colorMapPixelSizeInBytes,
inverted);
origin);
}
else
{
@ -141,7 +146,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
pixels,
palette.Array,
colorMapPixelSizeInBytes,
inverted);
origin);
}
}
@ -160,11 +165,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
case 8:
if (this.fileHeader.ImageType.IsRunLengthEncoded())
{
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 1, inverted);
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 1, origin);
}
else
{
this.ReadMonoChrome(this.fileHeader.Width, this.fileHeader.Height, pixels, inverted);
this.ReadMonoChrome(this.fileHeader.Width, this.fileHeader.Height, pixels, origin);
}
break;
@ -173,11 +178,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
case 16:
if (this.fileHeader.ImageType.IsRunLengthEncoded())
{
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 2, inverted);
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 2, origin);
}
else
{
this.ReadBgra16(this.fileHeader.Width, this.fileHeader.Height, pixels, inverted);
this.ReadBgra16(this.fileHeader.Width, this.fileHeader.Height, pixels, origin);
}
break;
@ -185,11 +190,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
case 24:
if (this.fileHeader.ImageType.IsRunLengthEncoded())
{
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 3, inverted);
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 3, origin);
}
else
{
this.ReadBgr24(this.fileHeader.Width, this.fileHeader.Height, pixels, inverted);
this.ReadBgr24(this.fileHeader.Width, this.fileHeader.Height, pixels, origin);
}
break;
@ -197,11 +202,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
case 32:
if (this.fileHeader.ImageType.IsRunLengthEncoded())
{
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 4, inverted);
this.ReadRle(this.fileHeader.Width, this.fileHeader.Height, pixels, 4, origin);
}
else
{
this.ReadBgra32(this.fileHeader.Width, this.fileHeader.Height, pixels, inverted);
this.ReadBgra32(this.fileHeader.Width, this.fileHeader.Height, pixels, origin);
}
break;
@ -228,8 +233,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// <param name="pixels">The <see cref="Buffer2D{TPixel}"/> to assign the palette to.</param>
/// <param name="palette">The color palette.</param>
/// <param name="colorMapPixelSizeInBytes">Color map size of one entry in bytes.</param>
/// <param name="inverted">Indicates, if the origin of the image is top left rather the bottom left (the default).</param>
private void ReadPaletted<TPixel>(int width, int height, Buffer2D<TPixel> pixels, byte[] palette, int colorMapPixelSizeInBytes, bool inverted)
/// <param name="origin">The image origin.</param>
private void ReadPaletted<TPixel>(int width, int height, Buffer2D<TPixel> pixels, byte[] palette, int colorMapPixelSizeInBytes, TgaImageOrigin origin)
where TPixel : unmanaged, IPixel<TPixel>
{
using (IManagedByteBuffer row = this.memoryAllocator.AllocateManagedByteBuffer(width, AllocationOptions.Clean))
@ -240,7 +245,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
for (int y = 0; y < height; y++)
{
this.currentStream.Read(row);
int newY = Invert(y, height, inverted);
int newY = InvertY(y, height, origin);
Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
switch (colorMapPixelSizeInBytes)
{
@ -257,7 +262,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
}
color.FromBgra5551(bgra);
pixelRow[x] = color;
int newX = InvertX(x, width, origin);
pixelRow[newX] = color;
}
break;
@ -267,7 +273,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
{
int colorIndex = rowSpan[x];
color.FromBgr24(Unsafe.As<byte, Bgr24>(ref palette[colorIndex * colorMapPixelSizeInBytes]));
pixelRow[x] = color;
int newX = InvertX(x, width, origin);
pixelRow[newX] = color;
}
break;
@ -277,7 +284,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
{
int colorIndex = rowSpan[x];
color.FromBgra32(Unsafe.As<byte, Bgra32>(ref palette[colorIndex * colorMapPixelSizeInBytes]));
pixelRow[x] = color;
int newX = InvertX(x, width, origin);
pixelRow[newX] = color;
}
break;
@ -295,8 +303,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// <param name="pixels">The <see cref="Buffer2D{TPixel}"/> to assign the palette to.</param>
/// <param name="palette">The color palette.</param>
/// <param name="colorMapPixelSizeInBytes">Color map size of one entry in bytes.</param>
/// <param name="inverted">Indicates, if the origin of the image is top left rather the bottom left (the default).</param>
private void ReadPalettedRle<TPixel>(int width, int height, Buffer2D<TPixel> pixels, byte[] palette, int colorMapPixelSizeInBytes, bool inverted)
/// <param name="origin">The image origin.</param>
private void ReadPalettedRle<TPixel>(int width, int height, Buffer2D<TPixel> pixels, byte[] palette, int colorMapPixelSizeInBytes, TgaImageOrigin origin)
where TPixel : unmanaged, IPixel<TPixel>
{
int bytesPerPixel = 1;
@ -309,7 +317,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
for (int y = 0; y < height; y++)
{
int newY = Invert(y, height, inverted);
int newY = InvertY(y, height, origin);
Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
int rowStartIdx = y * width * bytesPerPixel;
for (int x = 0; x < width; x++)
@ -348,7 +356,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
break;
}
pixelRow[x] = color;
int newX = InvertX(x, width, origin);
pixelRow[newX] = color;
}
}
}
@ -361,16 +370,36 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// <param name="width">The width of the image.</param>
/// <param name="height">The height of the image.</param>
/// <param name="pixels">The <see cref="Buffer2D{TPixel}"/> to assign the palette to.</param>
/// <param name="inverted">Indicates, if the origin of the image is top left rather the bottom left (the default).</param>
private void ReadMonoChrome<TPixel>(int width, int height, Buffer2D<TPixel> pixels, bool inverted)
/// <param name="origin">the image origin.</param>
private void ReadMonoChrome<TPixel>(int width, int height, Buffer2D<TPixel> pixels, TgaImageOrigin origin)
where TPixel : unmanaged, IPixel<TPixel>
{
bool isXInverted = origin == TgaImageOrigin.BottomRight || origin == TgaImageOrigin.TopRight;
if (isXInverted)
{
TPixel color = default;
for (int y = 0; y < height; y++)
{
int newY = InvertY(y, height, origin);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
for (int x = 0; x < width; x++)
{
var pixelValue = (byte)this.currentStream.ReadByte();
color.FromL8(Unsafe.As<byte, L8>(ref pixelValue));
int newX = InvertX(x, width, origin);
pixelSpan[newX] = color;
}
}
return;
}
using (IManagedByteBuffer row = this.memoryAllocator.AllocatePaddedPixelRowBuffer(width, 1, 0))
{
for (int y = 0; y < height; y++)
{
this.currentStream.Read(row);
int newY = Invert(y, height, inverted);
int newY = InvertY(y, height, origin);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
PixelOperations<TPixel>.Instance.FromL8Bytes(this.configuration, row.GetSpan(), pixelSpan, width);
}
@ -384,29 +413,50 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// <param name="width">The width of the image.</param>
/// <param name="height">The height of the image.</param>
/// <param name="pixels">The <see cref="Buffer2D{TPixel}"/> to assign the palette to.</param>
/// <param name="inverted">Indicates, if the origin of the image is top left rather the bottom left (the default).</param>
private void ReadBgra16<TPixel>(int width, int height, Buffer2D<TPixel> pixels, bool inverted)
/// <param name="origin">The image origin.</param>
private void ReadBgra16<TPixel>(int width, int height, Buffer2D<TPixel> pixels, TgaImageOrigin origin)
where TPixel : unmanaged, IPixel<TPixel>
{
TPixel color = default;
bool isXInverted = origin == TgaImageOrigin.BottomRight || origin == TgaImageOrigin.TopRight;
using (IManagedByteBuffer row = this.memoryAllocator.AllocatePaddedPixelRowBuffer(width, 2, 0))
{
for (int y = 0; y < height; y++)
{
this.currentStream.Read(row);
Span<byte> rowSpan = row.GetSpan();
int newY = InvertY(y, height, origin);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
if (!this.hasAlpha)
if (isXInverted)
{
// We need to set the alpha component value to fully opaque.
for (int x = 1; x < rowSpan.Length; x += 2)
for (int x = 0; x < width; x++)
{
rowSpan[x] = (byte)(rowSpan[x] | (1 << 7));
this.currentStream.Read(this.buffer, 0, 2);
if (!this.hasAlpha)
{
this.buffer[1] |= 1 << 7;
}
color.FromBgra5551(Unsafe.As<byte, Bgra5551>(ref this.buffer[0]));
int newX = InvertX(x, width, origin);
pixelSpan[newX] = color;
}
}
else
{
this.currentStream.Read(row);
Span<byte> rowSpan = row.GetSpan();
int newY = Invert(y, height, inverted);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
PixelOperations<TPixel>.Instance.FromBgra5551Bytes(this.configuration, rowSpan, pixelSpan, width);
if (!this.hasAlpha)
{
// We need to set the alpha component value to fully opaque.
for (int x = 1; x < rowSpan.Length; x += 2)
{
rowSpan[x] |= (1 << 7);
}
}
PixelOperations<TPixel>.Instance.FromBgra5551Bytes(this.configuration, rowSpan, pixelSpan, width);
}
}
}
}
@ -418,16 +468,36 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// <param name="width">The width of the image.</param>
/// <param name="height">The height of the image.</param>
/// <param name="pixels">The <see cref="Buffer2D{TPixel}"/> to assign the palette to.</param>
/// <param name="inverted">Indicates, if the origin of the image is top left rather the bottom left (the default).</param>
private void ReadBgr24<TPixel>(int width, int height, Buffer2D<TPixel> pixels, bool inverted)
/// <param name="origin">The image origin.</param>
private void ReadBgr24<TPixel>(int width, int height, Buffer2D<TPixel> pixels, TgaImageOrigin origin)
where TPixel : unmanaged, IPixel<TPixel>
{
bool isXInverted = origin == TgaImageOrigin.BottomRight || origin == TgaImageOrigin.TopRight;
if (isXInverted)
{
TPixel color = default;
for (int y = 0; y < height; y++)
{
int newY = InvertY(y, height, origin);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
for (int x = 0; x < width; x++)
{
this.currentStream.Read(this.buffer, 0, 3);
color.FromBgr24(Unsafe.As<byte, Bgr24>(ref this.buffer[0]));
int newX = InvertX(x, width, origin);
pixelSpan[newX] = color;
}
}
return;
}
using (IManagedByteBuffer row = this.memoryAllocator.AllocatePaddedPixelRowBuffer(width, 3, 0))
{
for (int y = 0; y < height; y++)
{
this.currentStream.Read(row);
int newY = Invert(y, height, inverted);
int newY = InvertY(y, height, origin);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
PixelOperations<TPixel>.Instance.FromBgr24Bytes(this.configuration, row.GetSpan(), pixelSpan, width);
}
@ -441,18 +511,38 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// <param name="width">The width of the image.</param>
/// <param name="height">The height of the image.</param>
/// <param name="pixels">The <see cref="Buffer2D{TPixel}"/> to assign the palette to.</param>
/// <param name="inverted">Indicates, if the origin of the image is top left rather the bottom left (the default).</param>
private void ReadBgra32<TPixel>(int width, int height, Buffer2D<TPixel> pixels, bool inverted)
/// <param name="origin">The image origin.</param>
private void ReadBgra32<TPixel>(int width, int height, Buffer2D<TPixel> pixels, TgaImageOrigin origin)
where TPixel : unmanaged, IPixel<TPixel>
{
TPixel color = default;
if (this.tgaMetadata.AlphaChannelBits == 8)
{
bool isXInverted = origin == TgaImageOrigin.BottomRight || origin == TgaImageOrigin.TopRight;
if (isXInverted)
{
for (int y = 0; y < height; y++)
{
int newY = InvertY(y, height, origin);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
for (int x = 0; x < width; x++)
{
this.currentStream.Read(this.buffer, 0, 4);
color.FromBgra32(Unsafe.As<byte, Bgra32>(ref this.buffer[0]));
int newX = InvertX(x, width, origin);
pixelSpan[newX] = color;
}
}
return;
}
using (IManagedByteBuffer row = this.memoryAllocator.AllocatePaddedPixelRowBuffer(width, 4, 0))
{
for (int y = 0; y < height; y++)
{
this.currentStream.Read(row);
int newY = Invert(y, height, inverted);
int newY = InvertY(y, height, origin);
Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
PixelOperations<TPixel>.Instance.FromBgra32Bytes(this.configuration, row.GetSpan(), pixelSpan, width);
@ -462,14 +552,13 @@ namespace SixLabors.ImageSharp.Formats.Tga
return;
}
TPixel color = default;
var alphaBits = this.tgaMetadata.AlphaChannelBits;
using (IManagedByteBuffer row = this.memoryAllocator.AllocatePaddedPixelRowBuffer(width, 4, 0))
{
for (int y = 0; y < height; y++)
{
this.currentStream.Read(row);
int newY = Invert(y, height, inverted);
int newY = InvertY(y, height, origin);
Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
Span<byte> rowSpan = row.GetSpan();
@ -478,7 +567,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
int idx = x * 4;
var alpha = alphaBits == 0 ? byte.MaxValue : rowSpan[idx + 3];
color.FromBgra32(new Bgra32(rowSpan[idx + 2], rowSpan[idx + 1], rowSpan[idx], (byte)alpha));
pixelRow[x] = color;
int newX = InvertX(x, width, origin);
pixelRow[newX] = color;
}
}
}
@ -492,8 +582,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// <param name="height">The height of the image.</param>
/// <param name="pixels">The <see cref="Buffer2D{TPixel}"/> to assign the palette to.</param>
/// <param name="bytesPerPixel">The bytes per pixel.</param>
/// <param name="inverted">Indicates, if the origin of the image is top left rather the bottom left (the default).</param>
private void ReadRle<TPixel>(int width, int height, Buffer2D<TPixel> pixels, int bytesPerPixel, bool inverted)
/// <param name="origin">The image origin.</param>
private void ReadRle<TPixel>(int width, int height, Buffer2D<TPixel> pixels, int bytesPerPixel, TgaImageOrigin origin)
where TPixel : unmanaged, IPixel<TPixel>
{
TPixel color = default;
@ -504,7 +594,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
this.UncompressRle(width, height, bufferSpan, bytesPerPixel);
for (int y = 0; y < height; y++)
{
int newY = Invert(y, height, inverted);
int newY = InvertY(y, height, origin);
Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
int rowStartIdx = y * width * bytesPerPixel;
for (int x = 0; x < width; x++)
@ -541,7 +631,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
break;
}
pixelRow[x] = color;
int newX = InvertX(x, width, origin);
pixelRow[newX] = color;
}
}
}
@ -609,18 +700,48 @@ namespace SixLabors.ImageSharp.Formats.Tga
/// Returns the y- value based on the given height.
/// </summary>
/// <param name="y">The y- value representing the current row.</param>
/// <param name="height">The height of the bitmap.</param>
/// <param name="inverted">Whether the bitmap is inverted.</param>
/// <param name="height">The height of the image.</param>
/// <param name="origin">The image origin.</param>
/// <returns>The <see cref="int"/> representing the inverted value.</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int InvertY(int y, int height, TgaImageOrigin origin)
{
switch (origin)
{
case TgaImageOrigin.BottomLeft:
case TgaImageOrigin.BottomRight:
return height - y - 1;
default:
return y;
}
}
/// <summary>
/// Returns the x- value based on the given width.
/// </summary>
/// <param name="x">The x- value representing the current column.</param>
/// <param name="width">The width of the image.</param>
/// <param name="origin">The image origin.</param>
/// <returns>The <see cref="int"/> representing the inverted value.</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int Invert(int y, int height, bool inverted) => (!inverted) ? height - y - 1 : y;
private static int InvertX(int x, int width, TgaImageOrigin origin)
{
switch (origin)
{
case TgaImageOrigin.TopRight:
case TgaImageOrigin.BottomRight:
return width - x - 1;
default:
return x;
}
}
/// <summary>
/// Reads the tga file header from the stream.
/// </summary>
/// <param name="stream">The <see cref="Stream"/> containing image data.</param>
/// <returns>true, if the image origin is top left.</returns>
private bool ReadFileHeader(Stream stream)
/// <returns>The image origin.</returns>
private TgaImageOrigin ReadFileHeader(Stream stream)
{
this.currentStream = stream;
@ -641,15 +762,9 @@ namespace SixLabors.ImageSharp.Formats.Tga
this.tgaMetadata.AlphaChannelBits = (byte)alphaBits;
this.hasAlpha = alphaBits > 0;
// TODO: bits 4 and 5 describe the image origin. See spec page 9. bit 4 is currently ignored.
// Theoretically the origin could also be top right and bottom right.
// Bit at position 5 of the descriptor indicates, that the origin is top left instead of bottom left.
if ((this.fileHeader.ImageDescriptor & (1 << 5)) != 0)
{
return true;
}
return false;
// Bits 4 and 5 describe the image origin.
var origin = (TgaImageOrigin)((this.fileHeader.ImageDescriptor & 0x30) >> 4);
return origin;
}
}
}

28
src/ImageSharp/Formats/Tga/TgaImageOrigin.cs
View File

@ -0,0 +1,28 @@
// Copyright (c) Six Labors and contributors.
// Licensed under the Apache License, Version 2.0.
namespace SixLabors.ImageSharp.Formats.Tga
{
internal enum TgaImageOrigin
{
/// <summary>
/// Bottom left origin.
/// </summary>
BottomLeft = 0,
/// <summary>
/// Bottom right origin.
/// </summary>
BottomRight = 1,
/// <summary>
/// Top left origin.
/// </summary>
TopLeft = 2,
/// <summary>
/// Top right origin.
/// </summary>
TopRight = 3,
}
}
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