using System;
using System.Buffers;
using System.Diagnostics.CodeAnalysis;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using StardewValley;
namespace StardewModdingAPI.Framework.Content
{
/// <summary>Encapsulates access and changes to image content being read from a data file.</summary>
internal class AssetDataForImage : AssetData<Texture2D>, IAssetDataForImage
{
/*********
** Fields
*********/
/// <summary>The minimum value to consider non-transparent.</summary>
/// <remarks>On Linux/macOS, fully transparent pixels may have an alpha up to 4 for some reason.</remarks>
private const byte MinOpacity = 5;
/*********
** Public methods
*********/
/// <summary>Construct an instance.</summary>
/// <param name="locale">The content's locale code, if the content is localized.</param>
/// <param name="assetName">The asset name being read.</param>
/// <param name="data">The content data being read.</param>
/// <param name="getNormalizedPath">Normalizes an asset key to match the cache key.</param>
/// <param name="onDataReplaced">A callback to invoke when the data is replaced (if any).</param>
public AssetDataForImage(string? locale, IAssetName assetName, Texture2D data, Func<string, string> getNormalizedPath, Action<Texture2D> onDataReplaced)
: base(locale, assetName, data, getNormalizedPath, onDataReplaced) { }
/// <inheritdoc />
public void PatchImage(IRawTextureData source, Rectangle? sourceArea = null, Rectangle? targetArea = null, PatchMode patchMode = PatchMode.Replace)
{
if (source == null)
throw new ArgumentNullException(nameof(source), "Can't patch from null source data.");
// get normalized bounds
this.GetPatchBounds(ref sourceArea, ref targetArea, source.Width, source.Height);
if (source.Data.Length < (sourceArea.Value.Bottom - 1) * source.Width + sourceArea.Value.Right)
throw new ArgumentException("Can't apply image patch because the source image is smaller than the source area.", nameof(source));
int areaX = sourceArea.Value.X;
int areaY = sourceArea.Value.Y;
int areaWidth = sourceArea.Value.Width;
int areaHeight = sourceArea.Value.Height;
// shortcut: if the area width matches the source image, we can apply the image as-is without needing
// to copy the pixels into a smaller subset. It's fine if the source is taller than the area, since we'll
// just ignore the extra data at the end of the pixel array.
if (areaWidth == source.Width)
{
this.PatchImageImpl(source.Data, source.Width, source.Height, sourceArea.Value, targetArea.Value, patchMode, areaY);
return;
}
// else copy the pixels within the smaller area & apply that
int pixelCount = areaWidth * areaHeight;
Color[] sourceData = ArrayPool<Color>.Shared.Rent(pixelCount);
try
{
for (int y = areaY, maxY = areaY + areaHeight; y < maxY; y++)
{
int sourceIndex = (y * source.Width) + areaX;
int targetIndex = (y - areaY) * areaWidth;
Array.Copy(source.Data, sourceIndex, sourceData, targetIndex, areaWidth);
}
this.PatchImageImpl(sourceData, source.Width, source.Height, sourceArea.Value, targetArea.Value, patchMode);
}
finally
{
ArrayPool<Color>.Shared.Return(sourceData);
}
}
/// <inheritdoc />
public void PatchImage(Texture2D source, Rectangle? sourceArea = null, Rectangle? targetArea = null, PatchMode patchMode = PatchMode.Replace)
{
if (source == null)
throw new ArgumentNullException(nameof(source), "Can't patch from a null source texture.");
// get normalized bounds
this.GetPatchBounds(ref sourceArea, ref targetArea, source.Width, source.Height);
if (!source.Bounds.Contains(sourceArea.Value))
throw new ArgumentOutOfRangeException(nameof(sourceArea), "The source area is outside the bounds of the source texture.");
// get source data & apply
int pixelCount = sourceArea.Value.Width * sourceArea.Value.Height;
Color[] sourceData = ArrayPool<Color>.Shared.Rent(pixelCount);
try
{
source.GetData(0, sourceArea, sourceData, 0, pixelCount);
this.PatchImageImpl(sourceData, source.Width, source.Height, sourceArea.Value, targetArea.Value, patchMode);
}
finally
{
ArrayPool<Color>.Shared.Return(sourceData);
}
}
/// <inheritdoc />
public bool ExtendImage(int minWidth, int minHeight)
{
if (this.Data.Width >= minWidth && this.Data.Height >= minHeight)
return false;
Texture2D original = this.Data;
Texture2D texture = new Texture2D(Game1.graphics.GraphicsDevice, Math.Max(original.Width, minWidth), Math.Max(original.Height, minHeight)).SetName(original.Name);
this.ReplaceWith(texture);
this.PatchImage(original);
return true;
}
/*********
** Private methods
*********/
/// <summary>Get the bounds for an image patch.</summary>
/// <param name="sourceArea">The source area to set if needed.</param>
/// <param name="targetArea">The target area to set if needed.</param>
/// <param name="sourceWidth">The width of the full source image.</param>
/// <param name="sourceHeight">The height of the full source image.</param>
private void GetPatchBounds([NotNull] ref Rectangle? sourceArea, [NotNull] ref Rectangle? targetArea, int sourceWidth, int sourceHeight)
{
sourceArea ??= new Rectangle(0, 0, sourceWidth, sourceHeight);
targetArea ??= new Rectangle(0, 0, Math.Min(sourceArea.Value.Width, this.Data.Width), Math.Min(sourceArea.Value.Height, this.Data.Height));
}
/// <summary>Overwrite part of the image.</summary>
/// <param name="sourceData">The image data to patch into the content.</param>
/// <param name="sourceWidth">The pixel width of the original source image.</param>
/// <param name="sourceHeight">The pixel height of the original source image.</param>
/// <param name="sourceArea">The part of the <paramref name="sourceData"/> to copy (or <c>null</c> to take the whole texture). This must be within the bounds of the <paramref name="sourceData"/> texture.</param>
/// <param name="targetArea">The part of the content to patch (or <c>null</c> to patch the whole texture). The original content within this area will be erased. This must be within the bounds of the existing spritesheet.</param>
/// <param name="patchMode">Indicates how an image should be patched.</param>
/// <param name="startRow">The row to start on, for the sourceData.</param>
/// <exception cref="ArgumentNullException">One of the arguments is null.</exception>
/// <exception cref="ArgumentOutOfRangeException">The <paramref name="targetArea"/> is outside the bounds of the spritesheet.</exception>
/// <exception cref="InvalidOperationException">The content being read isn't an image.</exception>
private void PatchImageImpl(Color[] sourceData, int sourceWidth, int sourceHeight, Rectangle sourceArea, Rectangle targetArea, PatchMode patchMode, int startRow = 0)
{
// get texture
Texture2D target = this.Data;
int pixelCount = sourceArea.Width * sourceArea.Height;
// validate
if (sourceArea.X < 0 || sourceArea.Y < 0 || sourceArea.Right > sourceWidth || sourceArea.Bottom > sourceHeight)
throw new ArgumentOutOfRangeException(nameof(sourceArea), "The source area is outside the bounds of the source texture.");
if (!target.Bounds.Contains(targetArea))
throw new ArgumentOutOfRangeException(nameof(targetArea), "The target area is outside the bounds of the target texture.");
if (sourceArea.Size != targetArea.Size)
throw new InvalidOperationException("The source and target areas must be the same size.");
// shortcut: replace the entire area
if (patchMode == PatchMode.Replace)
{
target.SetData(0, targetArea, sourceData, startRow * sourceArea.Width, pixelCount);
return;
}
// skip transparent pixels at the start & end (e.g. large spritesheet with a few sprites replaced)
int startIndex = -1;
int endIndex = -1;
{
for (int i = startRow * sourceArea.Width; i < pixelCount; i++)
{
if (sourceData[i].A >= AssetDataForImage.MinOpacity)
{
startIndex = i;
break;
}
}
if (startIndex == -1)
return; // blank texture
for (int i = startRow * sourceArea.Width + pixelCount - 1; i >= startIndex; i--)
{
if (sourceData[i].A >= AssetDataForImage.MinOpacity)
{
endIndex = i;
break;
}
}
if (endIndex == -1)
return; // ???
}
// update target rectangle
int sourceOffset;
{
int topOffset = startIndex / sourceArea.Width;
int bottomOffset = endIndex / sourceArea.Width;
targetArea = new(targetArea.X, targetArea.Y + topOffset, targetArea.Width, bottomOffset - topOffset + 1);
pixelCount = targetArea.Width * targetArea.Height;
sourceOffset = topOffset * sourceArea.Width;
}
// apply
Color[] mergedData = ArrayPool<Color>.Shared.Rent(pixelCount);
try
{
target.GetData(0, targetArea, mergedData, 0, pixelCount);
for (int i = startIndex; i <= endIndex; i++)
{
int targetIndex = i - sourceOffset;
Color above = sourceData[i];
Color below = mergedData[targetIndex];
// shortcut transparency
if (above.A < AssetDataForImage.MinOpacity)
continue;
if (below.A < AssetDataForImage.MinOpacity || above.A == byte.MaxValue)
mergedData[targetIndex] = above;
// merge pixels
else
{
// This performs a conventional alpha blend for the pixels, which are already
// premultiplied by the content pipeline. The formula is derived from
// https://blogs.msdn.microsoft.com/shawnhar/2009/11/06/premultiplied-alpha/.
float alphaBelow = 1 - (above.A / 255f);
mergedData[targetIndex] = new Color(
r: (int)(above.R + (below.R * alphaBelow)),
g: (int)(above.G + (below.G * alphaBelow)),
b: (int)(above.B + (below.B * alphaBelow)),
alpha: Math.Max(above.A, below.A)
);
}
}
target.SetData(0, targetArea, mergedData, 0, pixelCount);
}
finally
{
ArrayPool<Color>.Shared.Return(mergedData);
}
}
}
}