/// <summary> /// Performs the image resize operation by reading from a file and writing to a file. /// </summary> /// <param name="sourcePath">The path of the file to read from.</param> /// <param name="destinationPath">The path of the file to write to. The output directory must exist for processing to succeed.</param> /// <param name="instructions">Specifies how the source bitmap should be resized.</param> public static void Build(string sourcePath, string destinationPath, Instructions instructions) => Build(sourcePath, destinationPath, false, instructions);
/// <summary>
/// Performs the image resize operation by reading from a file and writing to a file.
/// </summary>
/// <param name="sourcePath">The path of the file to read from.</param>
/// <param name="destinationPath">The path of the file to write to.</param>
/// <param name="createDestinationDirectory">Specifies whether to create the output directory or not if it does not exist.</param>
/// <param name="instructions">Specifies how the source bitmap should be resized.</param>
public static void Build(string sourcePath, string destinationPath, bool createDestinationDirectory, Instructions instructions)
{
if (sourcePath == null)
{
throw new ArgumentNullException(nameof(sourcePath));
}
var sourceOptions = sourcePath == destinationPath ? SourceOptions.BufferInMemory
: SourceOptions.None;
Build(File.Open(sourcePath, FileMode.Open, FileAccess.Read, FileShare.Read), sourceOptions, destinationPath, createDestinationDirectory, instructions);
}
// Performs the actual bitmap resize operation.
// Only rendering occurs here. See 'Layout' for the math part of things. Neither 'dest' nor 'source' are disposed here!
private static void Render(Bitmap source, RectangleF copyRect, Size destSize, RectangleF targetRect, Instructions instructions, out Bitmap dest)
{
// Create new bitmap using calculated size.
dest = new Bitmap(destSize.Width, destSize.Height, PixelFormat.Format32bppArgb);
// Create graphics handle
using (var g = Graphics.FromImage(dest))
{
// HQ bi-cubic is 2 pass. It's only 30% slower than low quality, why not have HQ results?
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
// Ensures the edges are crisp
g.SmoothingMode = SmoothingMode.HighQuality;
// Prevents artifacts at the edges
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
// Ensures matted PNGs look decent
g.CompositingQuality = CompositingQuality.HighQuality;
// Prevents really ugly transparency issues
g.CompositingMode = CompositingMode.SourceOver;
// If the image doesn't support transparency, we need to fill the background color now.
var background = instructions.BackgroundColor;
// Find out if we can safely know that nothing will be showing through or around the image.
var nothingToShow = (source.PixelFormat == PixelFormat.Format24bppRgb ||
source.PixelFormat == PixelFormat.Format32bppRgb ||
source.PixelFormat == PixelFormat.Format48bppRgb) &&
targetRect.Width == destSize.Width && targetRect.Height == destSize.Height &&
targetRect.X == 0 && targetRect.Y == 0;
// Set the background to white if the background will be showing and the destination format doesn't support transparency.
if (background == Color.Transparent && instructions.Format == OutputFormat.Jpeg & !nothingToShow)
{
background = Color.White;
}
// Fill background
if (background != Color.Transparent)
{
g.Clear(background);
}
using (var ia = new ImageAttributes())
{
// Fixes the 50% gray border issue on bright white or dark images
ia.SetWrapMode(WrapMode.TileFlipXY);
// Make poly from rectF
var r = new PointF[3];
r[0] = targetRect.Location;
r[1] = new PointF(targetRect.Right, targetRect.Top);
r[2] = new PointF(targetRect.Left, targetRect.Bottom);
// Render!
g.DrawImage(source, r, copyRect, GraphicsUnit.Pixel, ia);
}
g.Flush(FlushIntention.Flush);
}
}
/// <summary>
/// Loads the bitmap from stream, processes, and renders, sending the result <see cref="Bitmap"/> to the <paramref name="consumer"/> callback for encoding or usage.
/// </summary>
/// <param name="source">The <see cref="Stream"/> to read from.</param>
/// <param name="sourceOptions">Specifies what should happen with the <paramref name="source"/> stream after processing.</param>
/// <param name="consumer">The callback that will receive the resized <see cref="Bitmap"/> for further processing (e.g. writing to a destination). The passed-in bitmap will be disposed immediately after callback invocation.</param>
/// <param name="instructions">Specifies how the source bitmap should be resized.</param>
private static void Build(Stream source, SourceOptions sourceOptions, Action <Bitmap> consumer, Instructions instructions)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
const SourceOptions validSourceOptions = SourceOptions.BufferInMemory
| SourceOptions.LeaveOpen
| SourceOptions.Rewind;
if ((sourceOptions & ~validSourceOptions) != 0)
{
throw new ArgumentOutOfRangeException(nameof(sourceOptions));
}
Debug.Assert(consumer != null, nameof(consumer) + " must not be null.");
if (instructions == null)
{
throw new ArgumentNullException(nameof(instructions));
}
var leaveSourceStreamOpen = (sourceOptions & SourceOptions.LeaveOpen) != 0;
var bufferSource = (sourceOptions & SourceOptions.BufferInMemory) != 0;
var originalPosition = (sourceOptions & SourceOptions.Rewind) == SourceOptions.Rewind ? source.Position : -1;
Bitmap destBitmap = null;
try
{
Stream underlyingStream = null;
Bitmap sourceBitmap = null;
try
{
// Buffer source stream if requested
underlyingStream = bufferSource ? StreamUtils.CopyToMemoryStream(source, true, 0x1000) : source;
// Allow early disposal (enables same-file edits)
if (bufferSource && !leaveSourceStreamOpen)
{
source.Dispose();
source = null;
}
// Load bitmap
sourceBitmap = new Bitmap(underlyingStream, !instructions.IgnoreICC);
// Use size
var originalSize = sourceBitmap.Size;
// Do math
Layout(originalSize, instructions, out RectangleF copyRect, out Size destSize, out RectangleF targetRect);
// Render to 'destBitmap'
Render(sourceBitmap, copyRect, destSize, targetRect, instructions, out destBitmap);
}
finally
{
try
{
// Dispose loaded bitmap instance
if (sourceBitmap != null)
{
sourceBitmap.Dispose();
}
}
finally
{
sourceBitmap = null; // Ensure reference is null
try
{
// Dispose buffer
if (underlyingStream != null && source != underlyingStream)
{
underlyingStream.Dispose();
}
}
finally
{
underlyingStream = null; // Ensure reference is null
// Dispose source stream or restore its position
if (!leaveSourceStreamOpen && source != null)
{
source.Dispose();
}
else if (originalPosition > -1 && source != null && source.CanSeek)
{
source.Position = originalPosition;
}
}
}
}
// Fire callback to write to disk or use Bitmap instance directly
consumer(destBitmap);
}
finally
{
// Temporary bitmap must be disposed
if (destBitmap != null)
{
destBitmap.Dispose();
destBitmap = null;
}
}
}
// Layout: size and cropping constraints are calculated here.
private static void Layout(Size originalSize, Instructions instructions, out RectangleF copyRect, out Size destSize, out RectangleF targetRect)
{
// Aspect ratio of the source image
var imageRatio = (double)originalSize.Width / (double)originalSize.Height;
// Target image size
SizeF targetSize;
// Target canvas size
SizeF canvasSize;
var originalRect = new RectangleF(0, 0, originalSize.Width, originalSize.Height);
copyRect = originalRect;
// Width should have already been validated
var width = instructions.Width;
Debug.Assert(width == null || width > 0, "There is an unexpected code path for setting " + nameof(Instructions) + "." + nameof(Instructions.Width) + " to a non-null and non-positive value.");
// Height should have already been validated
var height = instructions.Height;
Debug.Assert(height == null || height > 0, "There is an unexpected code path for setting " + nameof(Instructions) + "." + nameof(Instructions.Height) + " to a non-null and non-positive value.");
if (width.HasValue || height.HasValue)
{
// Establish constraint bounds
SizeF bounds = width.HasValue && height.HasValue
? new SizeF((float)width, (float)height)
: (width.HasValue
? new SizeF((float)width, (float)((double)width / imageRatio))
: (height.HasValue
? new SizeF((float)((double)height * imageRatio), (float)height)
: SizeF.Empty));
/* We now have width & height, our target size. It will only be a different aspect ratio from the image if both 'width' and 'height' are specified. */
var mode = instructions.Mode;
if (mode == FitMode.Max)
{
// FitMode.Max
canvasSize = targetSize = BoxMath.ScaleInside(copyRect.Size, bounds);
}
else if (mode == FitMode.Pad)
{
// FitMode.Pad
canvasSize = bounds;
targetSize = BoxMath.ScaleInside(copyRect.Size, canvasSize);
}
else if (mode == FitMode.Crop)
{
// FitMode.crop
// We auto-crop - so both target and area match the requested size
canvasSize = targetSize = bounds;
// Determine the size of the area we are copying
var sourceSize = BoxMath.RoundPoints(BoxMath.ScaleInside(canvasSize, copyRect.Size));
// Center the portion we are copying within the manualCropSize
copyRect = BoxMath.ToRectangle(BoxMath.CenterInside(sourceSize, copyRect));
}
else
{
// Stretch and carve both act like stretching, so do that:
canvasSize = targetSize = bounds;
}
}
else
{
// No dimensions specified, no fit mode needed. Use original dimensions
canvasSize = targetSize = originalSize;
}
// Now, unless upscaling is enabled, ensure the image is no larger than it was originally
var scale = instructions.Scale;
if (scale != ScaleMode.Both && BoxMath.FitsInside(originalSize, targetSize))
{
targetSize = originalSize;
copyRect = originalRect;
// And reset the canvas size, unless canvas upscaling is enabled.
if (scale != ScaleMode.UpscaleCanvas)
{
canvasSize = targetSize;
}
}
// May 12: require max dimension and round values to minimize rounding differences later.
canvasSize.Width = Math.Max(1, (float)Math.Round(canvasSize.Width));
canvasSize.Height = Math.Max(1, (float)Math.Round(canvasSize.Height));
targetSize.Width = Math.Max(1, (float)Math.Round(targetSize.Width));
targetSize.Height = Math.Max(1, (float)Math.Round(targetSize.Height));
destSize = new Size((int)canvasSize.Width, (int)canvasSize.Height);
targetRect = BoxMath.CenterInside(targetSize, new RectangleF(0, 0, canvasSize.Width, canvasSize.Height));
}
/// <summary> /// Performs the image resize operation by reading from a <see cref="Stream"/> and writing to a <see cref="Stream"/>. /// </summary> /// <param name="source">The stream to read from. The stream will be closed.</param> /// <param name="destination">The stream to write to. The stream will be closed.</param> /// <param name="instructions">Specifies how the source bitmap should be resized.</param> public static void Build(Stream source, Stream destination, Instructions instructions) => Build(source, SourceOptions.None, destination, false, instructions);
/// <summary> /// Performs the image resize operation by reading from a <see cref="Stream"/> and writing to a <see cref="Stream"/>. /// </summary> /// <param name="source">The stream to read from. This stream will be closed.</param> /// <param name="destination">The stream to write to.</param> /// <param name="leaveDestinationOpen">Specifies whether the <paramref name="destination"/> stream should be left open after processing.</param> /// <param name="instructions">Specifies how the source bitmap should be resized.</param> public static void Build(Stream source, Stream destination, bool leaveDestinationOpen, Instructions instructions) => Build(source, SourceOptions.None, destination, leaveDestinationOpen, instructions);
/// <summary>
/// Performs the image resize operation by reading from a <see cref="Stream"/> and writing to a <see cref="Stream"/>.
/// </summary>
/// <param name="source">The stream to read from.</param>
/// <param name="sourceOptions">Specifies what should happen with the <paramref name="source"/> stream after processing.</param>
/// <param name="destination">The stream to write to.</param>
/// <param name="leaveDestinationOpen">Specifies whether the <paramref name="destination"/> stream should be left open after processing.</param>
/// <param name="instructions">Specifies how the source bitmap should be resized.</param>
/// <remarks>
/// Ensure that the first stream you open will be safely closed if the second stream fails to open! This means a <c>using()</c> or <c>try</c>/<c>finally</c> clause.
/// </remarks>
public static void Build(Stream source, SourceOptions sourceOptions, Stream destination, bool leaveDestinationOpen, Instructions instructions)
{
if (destination == null)
{
throw new ArgumentNullException(nameof(destination));
}
Build(
source,
sourceOptions,
(Bitmap b) =>
{
try
{
// Encode from temp bitmap to target stream
Encode(b, destination, instructions);
}
finally
{
// Ensure target stream is disposed if requested
if (!leaveDestinationOpen)
{
destination.Dispose();
}
}
},
instructions);
}
/// <summary> /// Performs the image resize operation by reading from a <see cref="Stream"/> and writing to a file. /// </summary> /// <param name="source">The stream to read from. The stream will be closed.</param> /// <param name="destinationPath">The path of the file to write to.</param> /// <param name="createDestinationDirectory">Specifies whether to create the output directory or not if it does not exist.</param> /// <param name="instructions">Specifies how the source bitmap should be resized.</param> public static void Build(Stream source, string destinationPath, bool createDestinationDirectory, Instructions instructions) => Build(source, SourceOptions.None, destinationPath, createDestinationDirectory, instructions);
/// <summary> /// Performs the image resize operation by reading from a <see cref="Stream"/> and writing to a file. /// </summary> /// <param name="source">The stream to read from.</param> /// <param name="sourceOptions">Specifies what should happen with the <paramref name="source"/> stream after processing.</param> /// <param name="destinationPath">The path of the file to write to. The output directory must exist for processing to succeed.</param> /// <param name="instructions">Specifies how the source bitmap should be resized.</param> public static void Build(Stream source, SourceOptions sourceOptions, string destinationPath, Instructions instructions) => Build(source, sourceOptions, destinationPath, false, instructions);
