コード例 #1
0
        protected override void OnPaintSurface(SKPaintGLSurfaceEventArgs args)
        {
            base.OnPaintSurface(args);
            SKSize   info   = CanvasSize;
            SKCanvas canvas = args.Surface.Canvas;

            if (rectInfo.Width != info.Width || rectInfo.Height != info.Height)
            {
                rectInfo = new SKRect(0, 0, info.Width, info.Height);
                SetMainBitmapMatrix();
                SetTrashRects();
            }
            var rectImage = SkiaHelper.CalculateRectangle(rectInfo, outImageWidht, outImageHeight).rect;


            OnPaintSurface(canvas, rectImage, false);
            canvas.DrawSurrounding(rectInfo, rectImage, SkiaHelper.backgroundColor);
            DrawTrasRect(canvas);
        }
コード例 #2
0
        protected override void OnPaintSurface(SKPaintSurfaceEventArgs args)
        {
            base.OnPaintSurface(args);

            SKImageInfo info    = args.Info;
            SKSurface   surface = args.Surface;
            SKCanvas    canvas  = surface.Canvas;

            canvas.Clear(SkiaHelper.backgroundColor);

            // 计算显示位图的矩形
            var rect = SkiaHelper.CalculateRectangle(new SKRect(0, 0, info.Width, info.Height), bitmap);

            canvas.DrawBitmap(bitmap, rect.rect);

            // 计算用于显示裁剪矩形的矩阵变换
            SKMatrix bitmapScaleMatrix = SKMatrix.CreateIdentity();

            SKMatrix.CreateScaleTranslation(rect.scaleX, rect.scaleX, rect.rect.Left, rect.rect.Top);

            // 显示矩形
            SKRect scaledCropRect = bitmapScaleMatrix.MapRect(croppingRect.Rect);


            using (SKPaint edgeStroke = new SKPaint())
            {
                edgeStroke.Style       = SKPaintStyle.Stroke;
                edgeStroke.Color       = SKColors.White;
                edgeStroke.StrokeWidth = 3;
                edgeStroke.IsAntialias = true;
                canvas.DrawRect(scaledCropRect, edgeStroke);
            }

            canvas.DrawSurrounding(rect.rect, scaledCropRect, SKColors.Gray.WithAlpha(190));

            // Display heavier corners
            using (SKPaint cornerStroke = new SKPaint())
                using (SKPath path = new SKPath())
                {
                    cornerStroke.Style       = SKPaintStyle.Stroke;
                    cornerStroke.Color       = SKColors.White;
                    cornerStroke.StrokeWidth = 7;

                    path.MoveTo(scaledCropRect.Left, scaledCropRect.Top + corner);
                    path.LineTo(scaledCropRect.Left, scaledCropRect.Top);
                    path.LineTo(scaledCropRect.Left + corner, scaledCropRect.Top);

                    path.MoveTo(scaledCropRect.Right - corner, scaledCropRect.Top);
                    path.LineTo(scaledCropRect.Right, scaledCropRect.Top);
                    path.LineTo(scaledCropRect.Right, scaledCropRect.Top + corner);

                    path.MoveTo(scaledCropRect.Right, scaledCropRect.Bottom - corner);
                    path.LineTo(scaledCropRect.Right, scaledCropRect.Bottom);
                    path.LineTo(scaledCropRect.Right - corner, scaledCropRect.Bottom);

                    path.MoveTo(scaledCropRect.Left + corner, scaledCropRect.Bottom);
                    path.LineTo(scaledCropRect.Left, scaledCropRect.Bottom);
                    path.LineTo(scaledCropRect.Left, scaledCropRect.Bottom - corner);

                    canvas.DrawPath(path, cornerStroke);
                }

            // 反转变换以进行触摸跟踪
            bitmapScaleMatrix.TryInvert(out inverseBitmapMatrix);
        }