/// <summary>
/// Merges two images taking into consideration their alpha values.
/// </summary>
/// <param name="bmpBg">The background Image</param>
/// <param name="bmpTop">The image that goes on top of the background</param>
/// <param name="xBg">Left corner position of background</param>
/// <param name="yBg">Top corner position of the background</param>
/// <param name="xTop">Left corner position of the top image</param>
/// <param name="yTop">Top corner position of the top image</param>
/// <returns>Returns an interface to the image</returns>
IImageAdapterUnmanaged IImageAdapterUnmanaged.Merge(IImageAdapterUnmanaged bmpBg, IImageAdapterUnmanaged bmpTop, int xBg, int yBg, int xTop, int yTop)
{
System.Diagnostics.Debug.WriteLine("Merge() started");
#if DEBUG
ImageUtility.ToImageFile(bmpBg, System.IO.Path.Combine(System.IO.Path.GetTempPath(), "Before_Merge_Bg.png"));
ImageUtility.ToImageFile(bmpTop, System.IO.Path.Combine(System.IO.Path.GetTempPath(), "Before_Merge_Top.png"));
#endif // debug
#if DEBUG
ImageUtility.ToImageFile((IImageAdapter)bmpBg, System.IO.Path.Combine(System.IO.Path.GetTempPath(), "Merge_BgImage.bmp"));
ImageUtility.ToImageFile((IImageAdapter)bmpTop, System.IO.Path.Combine(System.IO.Path.GetTempPath(), "Merge_TopImage.bmp"));
#endif // DEBUG
Rectangle rBg = new Rectangle(xBg, yBg, bmpBg.Width, bmpBg.Height);
Rectangle rTop = new Rectangle(xTop, yTop, bmpTop.Width, bmpTop.Height);
System.Diagnostics.Debug.WriteLine("Merge() \n\nrBg " + rBg.ToString() + "\nrTop " + rTop.ToString());
if (Rectangle.Intersect(rBg, rTop) != rTop)
{
throw new ArgumentOutOfRangeException("Top BMP must be inside Bg one");
}
int maxAlpha = 0;
float bgAlpha = 0;
float topAlpha = 0;
// Copy Color from background image into this (same as cloning bg image into 'this')
ImageAdapter temp = new ImageAdapter((IImageAdapter)bmpBg);
System.Diagnostics.Debug.WriteLine("Merge1() : Before the loop");
for (int x = rBg.Left; x < rBg.Right; x++)
{
for (int y = rBg.Top; y < rBg.Bottom; y++)
{
if (rTop.Contains(x, y))
{
IColor colorBg = bmpBg[x - rBg.Left, y - rBg.Top];
IColor colorTop = bmpTop[x - rTop.Left, y - rTop.Top];
maxAlpha = Math.Max(colorBg.A, colorTop.A);
topAlpha = (float)colorTop.Alpha;
bgAlpha = (float)((1f - colorTop.Alpha) * colorBg.Alpha);
IColor color = new ColorByte((byte)maxAlpha,
(byte)(bgAlpha * colorBg.R + topAlpha * colorTop.R),
(byte)(bgAlpha * colorBg.G + topAlpha * colorTop.G),
(byte)(bgAlpha * colorBg.B + topAlpha * colorTop.B));
temp[x - rBg.Left, y - rBg.Top] = color;
}
}
}
#if DEBUG
ImageUtility.ToImageFile(temp, System.IO.Path.Combine(System.IO.Path.GetTempPath(), "After_Merge_This.png"));
#endif
return((IImageAdapterUnmanaged)temp);
}
private void InternalConstructor(Bitmap bmp)
{
if (bmp == null)
{
throw new ArgumentNullException("Bitmap passed in is null");
}
_colors = new IColor[bmp.Width, bmp.Height];
_metadataInfo = new MetadataInfo(bmp.PropertyItems);
//Verify that metadata correctly set the DPI
//In the case where no dpi meta is stored with the image it defaults to the screen resolution
//we fix that here in the metadata info
Point metaDpi = MetadataInfoHelper.GetDpi(_metadataInfo);
Point bmpDpi = new Point((int)Math.Round(bmp.HorizontalResolution), (int)Math.Round(bmp.VerticalResolution));
if (!metaDpi.Equals(bmpDpi))
{
MetadataInfoHelper.SetDpi(_metadataInfo, bmpDpi);
}
ImageUtility image = null;
try
{
image = new ImageUtility(bmp); // Conversion to 32 bits done internally.
image.GetSetPixelUnsafeBegin();
byte[] BGRAStream = image.GetStreamBufferBGRA();
image.GetSetPixelUnsafeRollBack();
int size = BGRAStream.Length;
for (int index = 0, x = 0, y = 0; index < size; index += 4, x++) // flat array to remove the cost of the computation (x + y *x)
{
if (x >= Width)
{
x = 0; y++;
}
_colors[x, y] = new ColorByte(BGRAStream[index + 3], BGRAStream[index + 2], BGRAStream[index + 1], BGRAStream[index]);
if (_colors[x, y].ARGB == 0)
{
_colors[x, y].IsEmpty = true;
}
}
BGRAStream = null;
}
finally
{
if (image != null)
{
image.Dispose(); image = null;
}
GC.Collect(GC.MaxGeneration);
}
}
