public void DrawSurface(CGContext ctx, CGRect viewBounds, SkiaSharp.SKImageInfo info, SkiaSharp.SKSurface surface)
{
if (info.Width == 0 || info.Height == 0)
{
return;
}
surface.Canvas.Flush();
// draw the image onto the context
using (var colorSpace = CGColorSpace.CreateDeviceRGB())
using (var image = new CGImage(info.Width, info.Height, BitsPerByte, info.BytesPerPixel * BitsPerByte, info.RowBytes, colorSpace, BitmapFlags, dataProvider, null, false, CGColorRenderingIntent.Default))
{
#if __IOS__ || __TVOS__ || __WATCHOS__ || HAS_UNO
// we need to flip the image as we are mixing CoreGraphics and UIKit functions:
// https://developer.apple.com/library/ios/documentation/2DDrawing/Conceptual/DrawingPrintingiOS/GraphicsDrawingOverview/GraphicsDrawingOverview.html#//apple_ref/doc/uid/TP40010156-CH14-SW26
ctx.SaveState();
ctx.TranslateCTM(0, viewBounds.Height);
ctx.ScaleCTM(1, -1);
// draw the image
ctx.DrawImage(viewBounds, image);
ctx.RestoreState();
#elif __MACOS__
// draw the image
ctx.DrawImage(viewBounds, image);
#else
#error Plaform-specific code missing
#endif
}
}
private SkiaSharp.SKSurface CreateSurface(out SkiaSharp.SKImageInfo info)
{
// get context details
info = this.info;
// if there are no pixels, clean up and return
if (info.Width == 0 || info.Height == 0)
{
Dispose();
return(null);
}
// if the memory size has changed, then reset the underlying memory
if (bitmap?.Handle == IntPtr.Zero || bitmap?.Width != info.Width || bitmap?.Height != info.Height)
{
FreeBitmap();
}
// create the bitmap data if we need it
if (bitmap == null)
{
bitmap = ABitmap.CreateBitmap(info.Width, info.Height, ABitmap.Config.Argb8888);
}
return(SkiaSharp.SKSurface.Create(info, bitmap.LockPixels(), info.RowBytes));
}
public SkiaSharp.SKSurface CreateSurface(CGRect contentsBounds, nfloat scale, out SkiaSharp.SKImageInfo info)
{
contentsBounds.Width *= scale;
contentsBounds.Height *= scale;
// apply a scale
// get context details
this.info = info = new SkiaSharp.SKImageInfo((int)contentsBounds.Width, (int)contentsBounds.Height);
// if there are no pixels, clean up and return
if (info.Width == 0 || info.Height == 0)
{
FreeBitmap();
this.info = SkiaSharp.SKImageInfo.Empty;
return(null);
}
// if the memory size has changed, then reset the underlying memory
if (bitmapData?.Length != (nuint)info.BytesSize)
{
FreeBitmap();
}
// allocate a memory block for the drawing process
if (bitmapData == null)
{
bitmapData = NSMutableData.FromLength(info.BytesSize);
dataProvider = new CGDataProvider(bitmapData.MutableBytes, info.BytesSize, Dummy);
Element.OnSizeChanged((float)contentsBounds.Width, (float)contentsBounds.Height);
}
return(SkiaSharp.SKSurface.Create(info, bitmapData.MutableBytes, info.RowBytes));
}
void OnCanvasViewPaintSurface(object sender, SkiaSharp.Views.Forms.SKPaintSurfaceEventArgs args)
{
SkiaSharp.SKImageInfo info = args.Info;
SkiaSharp.SKSurface surface = args.Surface;
SkiaSharp.SKCanvas canvas = surface.Canvas;
canvas.Clear();
SkiaSharp.SKRect bounds;
SkiaSharp.SKPath path = SkiaSharp.SKPath.ParseSvgPathData((string)this.Resources["PathString"]);
path.GetTightBounds(out bounds);
SkiaSharp.SKPaint paint = new SkiaSharp.SKPaint
{
Style = SkiaSharp.SKPaintStyle.Stroke,
Color = SkiaSharp.SKColors.Black,
StrokeWidth = 10,
StrokeCap = SkiaSharp.SKStrokeCap.Round,
StrokeJoin = SkiaSharp.SKStrokeJoin.Round
};
canvas.Translate(info.Width / 2, info.Height / 2);
canvas.Scale(info.Width / (bounds.Width + paint.StrokeWidth),
info.Height / (bounds.Height + paint.StrokeWidth));
canvas.Translate(-bounds.MidX, -bounds.MidY);
canvas.DrawPath(path, paint);
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
Element?.Gesture?.Clear();
RemoveObserver(this, keyPath: boundsPath);
RemoveObserver(this, keyPath: framePath);
}
base.Dispose(disposing);
// make sure we free the image data
FreeBitmap();
info = SkiaSharp.SKImageInfo.Empty;
}
public static SkiaSharp.SKBitmap?ToBitmap(this SkiaSharp.SKPicture skPicture, SkiaSharp.SKColor background, float scaleX, float scaleY, SkiaSharp.SKColorType skColorType, SkiaSharp.SKAlphaType skAlphaType, SkiaSharp.SKColorSpace skColorSpace)
{
var width = skPicture.CullRect.Width * scaleX;
var height = skPicture.CullRect.Height * scaleY;
if (!(width > 0) || !(height > 0))
{
return(null);
}
var skImageInfo = new SkiaSharp.SKImageInfo((int)width, (int)height, skColorType, skAlphaType, skColorSpace);
var skBitmap = new SkiaSharp.SKBitmap(skImageInfo);
using var skCanvas = new SkiaSharp.SKCanvas(skBitmap);
Draw(skPicture, background, scaleX, scaleY, skCanvas);
return(skBitmap);
}
protected void UpdateCanvasSize(int w, int h, float density = 1f)
{
if (density != 1)
{
info = new SkiaSharp.SKImageInfo((int)(w / density), (int)(h / density), SkiaSharp.SKColorType.Rgba8888, SkiaSharp.SKAlphaType.Premul);
}
else
{
info = new SkiaSharp.SKImageInfo(w, h, SkiaSharp.SKColorType.Rgba8888, SkiaSharp.SKAlphaType.Premul);
}
// if there are no pixels, clean up
if (info.Width == 0 || info.Height == 0)
{
FreeBitmap();
}
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
_disposed = true;
if (element != null)
{
element.SurfaceInvalidated -= Invalidate;
element.Gesture?.Clear();
}
OnFocusChangeListener = null;
_tracker?.Dispose();
}
FreeBitmap();
info = SkiaSharp.SKImageInfo.Empty;
base.Dispose(disposing);
}
protected override void OnRender(DrawingContext drawingContext)
{
base.OnRender(drawingContext);
if (designMode)
{
return;
}
if (Visibility != Visibility.Visible)
{
return;
}
var size = CreateSize(out var scaleX, out var scaleY);
if (size.Width <= 0 || size.Height <= 0)
{
return;
}
var info = new SkiaSharp.SKImageInfo(size.Width, size.Height, SkiaSharp.SKImageInfo.PlatformColorType, SkiaSharp.SKAlphaType.Premul, SKSvgSettings.s_srgb);
// reset the bitmap if the size has changed
if (bitmap == null || info.Width != bitmap.PixelWidth || info.Height != bitmap.PixelHeight)
{
bitmap = new WriteableBitmap(info.Width, size.Height, 96 * scaleX, 96 * scaleY, PixelFormats.Pbgra32, null);
}
// draw on the bitmap
bitmap.Lock();
using (var surface = SkiaSharp.SKSurface.Create(info, bitmap.BackBuffer, bitmap.BackBufferStride))
{
OnPaintSurface(new SKPaintSurfaceEventArgs(surface, info));
}
// draw the bitmap to the screen
bitmap.AddDirtyRect(new Int32Rect(0, 0, info.Width, size.Height));
bitmap.Unlock();
drawingContext.DrawImage(bitmap, new Rect(0, 0, ActualWidth, ActualHeight));
}
public SKPaintSurfaceEventArgs(SkiaSharp.SKSurface surface, SkiaSharp.SKImageInfo info)
{
Surface = surface;
Info = info;
}
protected override void OnDetachedFromWindow()
{
FreeBitmap();
info = SkiaSharp.SKImageInfo.Empty;
base.OnDetachedFromWindow();
}
void UpdateCanvasInfo(CGRect frame, System.nfloat scale)
{
info = new SkiaSharp.SKImageInfo((int)(Frame.Width * scale), (int)(frame.Height * scale));
}
public static BitmapInfo GetBitmapInfo(SkiaSharp.SKImageInfo info, int rowBytes = 0)
{
var fmt = ToPixelFormat((info.ColorType, info.AlphaType));
return(new BitmapInfo(info.Width, info.Height, fmt, Math.Max(info.RowBytes, rowBytes)));
}