C# CGContext.AddRects方法代码示例

	public override void DrawInContext (CGContext context)
	{
		// Drawing with a white stroke color
		context.SetRGBStrokeColor (1, 1, 1, 1);
		// And drawing with a blue fill color
		context.SetRGBFillColor (0, 0, 1, 1);
		// Draw them with a 2 stroke width so they are a bit more visible.
		context.SetLineWidth (2);
		
		// Add Rect to the current path, then stroke it
		context.AddRect (new RectangleF (30, 30, 60, 60));
		context.StrokePath ();
		
		// Stroke Rect convenience that is equivalent to above
		context.StrokeRect (new RectangleF (30, 120, 60, 60));
		
		// Stroke rect convenience equivalent to the above, plus a call to context.SetLineWidth ().
		context.StrokeRectWithWidth (new RectangleF (30, 210, 60, 60), 10);
		// Demonstate the stroke is on both sides of the path.
		context.SaveState ();
		context.SetRGBStrokeColor (1, 0, 0, 1);
		context.StrokeRectWithWidth (new RectangleF (30, 210, 60, 60), 2);
		context.RestoreState ();
		
		var rects = new RectangleF []
		{
			new RectangleF (120, 30, 60, 60),
			new RectangleF (120, 120, 60, 60),
			new RectangleF (120, 210, 60, 60),
		};
		// Bulk call to add rects to the current path.
		context.AddRects (rects);
		context.StrokePath ();
		
		// Create filled rectangles via two different paths.
		// Add/Fill path
		context.AddRect (new RectangleF (210, 30, 60, 60));
		context.FillPath ();
		// Fill convienience.
		context.FillRect (new RectangleF (210, 120, 60, 60));
	}	

//.........这里部分代码省略.........
            new RectangleF(170, 280, 120, 120),
        };

        // Linear Gradients
        PointF start, end;

        // Clip to area to draw the gradient, and draw it. Since we are clipping, we save the graphics state
        // so that we can revert to the previous larger area.
        context.SaveState();
        context.ClipToRect(clips[0]);

        // A linear gradient requires only a starting & ending point.
        // The colors of the gradient are linearly interpolated along the line segment connecting these two points
        // A gradient location of 0 means that color is expressed fully at the 'start' point
        // a location of 1 means that color is expressed fully at the 'end' point.
        // The gradient fills outwards perpendicular to the line segment connectiong start & end points
        // (which is why we need to clip the context, or the gradient would fill beyond where we want it to).
        // The gradient options (last) parameter determines what how to fill the clip area that is "before" and "after"
        // the line segment connecting start & end.
        start = demoLGStart(clips[0]);
        end = demoLGEnd(clips[0]);
        context.DrawLinearGradient(gradient, start, end, 0);
        context.RestoreState();

        // Same as above for each combination of CGGradientDrawingOptions.DrawsBeforeStartLocation & CGGradientDrawingOptions.DrawsAfterEndLocation

        context.SaveState();
        context.ClipToRect(clips[1]);
        start = demoLGStart(clips[1]);
        end = demoLGEnd(clips[1]);
        context.DrawLinearGradient(gradient, start, end, CGGradientDrawingOptions.DrawsBeforeStartLocation);
        context.RestoreState();

        context.SaveState();
        context.ClipToRect(clips[2]);
        start = demoLGStart(clips[2]);
        end = demoLGEnd(clips[2]);
        context.DrawLinearGradient(gradient, start, end, CGGradientDrawingOptions.DrawsAfterEndLocation);
        context.RestoreState();

        context.SaveState();
        context.ClipToRect(clips[3]);
        start = demoLGStart(clips[3]);
        end = demoLGEnd(clips[3]);
        context.DrawLinearGradient(gradient, start, end, CGGradientDrawingOptions.DrawsBeforeStartLocation | CGGradientDrawingOptions.DrawsAfterEndLocation);
        context.RestoreState();

        // Radial Gradients

        float startRadius, endRadius;

        // Clip to area to draw the gradient, and draw it. Since we are clipping, we save the graphics state
        // so that we can revert to the previous larger area.
        context.SaveState();
        context.ClipToRect(clips[4]);

        // A radial gradient requires a start & end point as well as a start & end radius.
        // Logically a radial gradient is created by linearly interpolating the center, radius and color of each
        // circle using the start and end point for the center, start and end radius for the radius, and the color ramp
        // inherant to the gradient to create a set of stroked circles that fill the area completely.
        // The gradient options specify if this interpolation continues past the start or end points as it does with
        // linear gradients.
        start = end = demoRGCenter(clips[4]);
        startRadius = demoRGInnerRadius(clips[4]);
        endRadius = demoRGOuterRadius(clips[4]);
        context.DrawRadialGradient(gradient, start, startRadius, end, endRadius, 0);
        context.RestoreState();

        // Same as above for each combination of CGGradientDrawingOptions.DrawsBeforeStartLocation & CGGradientDrawingOptions.DrawsAfterEndLocation

        context.SaveState();
        context.ClipToRect(clips[5]);
        start = end = demoRGCenter(clips[5]);
        startRadius = demoRGInnerRadius(clips[5]);
        endRadius = demoRGOuterRadius(clips[5]);
        context.DrawRadialGradient(gradient, start, startRadius, end, endRadius, CGGradientDrawingOptions.DrawsBeforeStartLocation);
        context.RestoreState();

        context.SaveState();
        context.ClipToRect(clips[6]);
        start = end = demoRGCenter(clips[6]);
        startRadius = demoRGInnerRadius(clips[6]);
        endRadius = demoRGOuterRadius(clips[6]);
        context.DrawRadialGradient(gradient, start, startRadius, end, endRadius, CGGradientDrawingOptions.DrawsAfterEndLocation);
        context.RestoreState();

        context.SaveState();
        context.ClipToRect(clips[7]);
        start = end = demoRGCenter(clips[7]);
        startRadius = demoRGInnerRadius(clips[7]);
        endRadius = demoRGOuterRadius(clips[7]);
        context.DrawRadialGradient(gradient, start, startRadius, end, endRadius, CGGradientDrawingOptions.DrawsBeforeStartLocation | CGGradientDrawingOptions.DrawsAfterEndLocation);
        context.RestoreState();

        // Show the clipping areas
        context.SetLineWidth(2);
        context.SetRGBStrokeColor(1, 0, 0, 1);
        context.AddRects(clips);
        context.StrokePath();
    }