/
ImageUtils.cs
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/
ImageUtils.cs
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// Copyright (c) 2009 Alex Fajkowski, Apparent Logic LLC
// C# port Copyright (C) 2010 Miguel de Icaza.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using MonoTouch.UIKit;
using MonoTouch.CoreGraphics;
using System.Drawing;
namespace OpenFlowSharp
{
public static class ImageUtils
{
public static UIImage AddImageReflection (UIImage image, float reflectionFraction)
{
int reflectionHeight = (int) (image.Size.Height * reflectionFraction);
// Create a 2 bit CGImage containing a gradient that will be used for masking the
// main view content to create the 'fade' of the reflection. The CGImageCreateWithMask
// function will stretch the bitmap image as required, so we can create a 1 pixel wide gradient
// gradient is always black and white and the mask must be in the gray colorspace
var colorSpace = CGColorSpace.CreateDeviceGray ();
// Creat the bitmap context
var gradientBitmapContext = new CGBitmapContext (IntPtr.Zero, 1, reflectionHeight, 8, 0, colorSpace, CGImageAlphaInfo.None);
// define the start and end grayscale values (with the alpha, even though
// our bitmap context doesn't support alpha the gradien requires it)
float [] colors = { 0, 1, 1, 1 };
// Create the CGGradient and then release the gray color space
var grayScaleGradient = new CGGradient (colorSpace, colors, null);
colorSpace.Dispose ();
// create the start and end points for the gradient vector (straight down)
var gradientStartPoint = new PointF (0, reflectionHeight);
var gradientEndPoint = PointF.Empty;
// draw the gradient into the gray bitmap context
gradientBitmapContext.DrawLinearGradient (grayScaleGradient, gradientStartPoint,
gradientEndPoint, CGGradientDrawingOptions.DrawsAfterEndLocation);
grayScaleGradient.Dispose ();
// Add a black fill with 50% opactiy
gradientBitmapContext.SetGrayFillColor (0, 0.5f);
gradientBitmapContext.FillRect (new RectangleF (0, 0, 1, reflectionHeight));
// conver the context into a CGImage and release the context
var gradientImageMask = gradientBitmapContext.ToImage ();
gradientBitmapContext.Dispose ();
// create an image by masking the bitmap of the mainView content with the gradient view
// then release the pre-masked content bitmap and the gradient bitmap
var reflectionImage = image.CGImage.WithMask (gradientImageMask);
gradientImageMask.Dispose ();
var size = new SizeF (image.Size.Width, image.Size.Height + reflectionHeight);
// Use BeginImageContextWithOptions for retina images (only available on is 4.0 and up).
// http://stackoverflow.com/questions/6965873/drawing-on-the-retina-display-using-coregraphics-image-pixelated
if (UIScreen.MainScreen.RespondsToSelector(new Selector("scale")))
{
UIGraphics.BeginImageContextWithOptions(size, false, UIScreen.MainScreen.Scale);
}
else
{
UIGraphics.BeginImageContext (size);
}
image.Draw (PointF.Empty);
var context = UIGraphics.GetCurrentContext ();
context.DrawImage (new RectangleF (0, image.Size.Height, image.Size.Width, reflectionHeight), reflectionImage);
var result = UIGraphics.GetImageFromCurrentImageContext ();
UIGraphics.EndImageContext ();
reflectionImage.Dispose ();
return result;
}
}
}