public static void ApplyMatrixMultiplier(this Image sourceImage, double[,] matrixMultiplier)
{
unsafe
{
DLLImports.gdImageStruct *pStruct = (DLLImports.gdImageStruct *)sourceImage.gdImageStructPtr;
for (int y = 0; y < sourceImage.HeightInPixels; y++)
{
for (int x = 0; x < sourceImage.WidthInPixels; x++)
{
int currentColor = pStruct->tpixels[y][x];
pStruct->tpixels[y][x] = ApplyFilter(currentColor, matrixMultiplier);
}
}
}
}
//Creating an avatar of the image
public static Image CircleCrop(this Image sourceImage)
{
int radius, diameter;
if (sourceImage.HeightInPixels < sourceImage.WidthInPixels)
{
radius = sourceImage.HeightInPixels / 2;
}
else
{
radius = sourceImage.WidthInPixels / 2;
}
diameter = 2 * radius;
Image destinationImage = Image.Create(diameter, diameter);
unsafe
{
DLLImports.gdImageStruct *pStruct = (DLLImports.gdImageStruct *)sourceImage.gdImageStructPtr;
DLLImports.gdImageStruct *fStruct = (DLLImports.gdImageStruct *)destinationImage.gdImageStructPtr;
for (int y = 0; y < diameter; y++)
{
for (int x = 0; x < diameter; x++)
{
int currentColor = pStruct->tpixels[y][x];
if ((x - radius) * (x - radius) + (y - radius) * (y - radius) > (radius * radius))
{
//mask to just get the alpha value (7 bits)
double currentAlpha = (currentColor >> 24) & 0xff;
currentAlpha = 127;
//make a new color with the new alpha to set the pixel
currentColor = (currentColor & 0x00ffffff | ((int)currentAlpha << 24));
}
fStruct->tpixels[y][x] = currentColor;
}
}
}
return(destinationImage);
}
public static Image Load(Stream stream)
{
if (stream != null)
{
unsafe
{
IntPtr pNativeImage = IntPtr.Zero;
var wrapper = new gdStreamWrapper(stream);
pNativeImage = DLLImports.gdImageCreateFromPngCtx(ref wrapper.IOCallbacks);
DLLImports.gdImageStruct *pStruct = (DLLImports.gdImageStruct *)pNativeImage;
Image toRet = Image.Create(pStruct->sx, pStruct->sx);
DLLImports.gdImageDestroy(toRet.gdImageStructPtr);
toRet.gdImageStructPtr = pNativeImage;
return(toRet);
}
}
else
{
throw new InvalidOperationException(SR.NullStreamReferenced);
}
}
//Transparency
public static void SetAlphaPercentage(this Image sourceImage, double opacityMultiplier)
{
if (opacityMultiplier > 1 || opacityMultiplier < 0)
{
throw new InvalidOperationException(SR.Format(SR.InvalidTransparencyPercent, opacityMultiplier));
}
double alphaAdjustment = 1 - opacityMultiplier;
unsafe
{
DLLImports.gdImageStruct *pStruct = (DLLImports.gdImageStruct *)sourceImage.gdImageStructPtr;
for (int y = 0; y < sourceImage.HeightInPixels; y++)
{
for (int x = 0; x < sourceImage.WidthInPixels; x++)
{
int currentColor = pStruct->tpixels[y][x];
//mask to just get the alpha value (7 bits)
double currentAlpha = (currentColor >> 24) & 0xff;
//if the current alpha is transparent
//dont bother/ skip over
if (currentAlpha == 127)
{
continue;
}
//calculate the new alpha value given the adjustment
currentAlpha += (127 - currentAlpha) * alphaAdjustment;
//make a new color with the new alpha to set the pixel
currentColor = (currentColor & 0x00ffffff | ((int)currentAlpha << 24));
pStruct->tpixels[y][x] = currentColor;
}
}
}
}
//Stamping an Image onto another
public static void Draw(this Image destinationImage, Image sourceImage, int xOffset, int yOffset)
{
//turn alpha blending on for drawing
DLLImports.gdImageAlphaBlending(destinationImage.gdImageStructPtr, 1);
unsafe
{
DLLImports.gdImageStruct *pStructSource = (DLLImports.gdImageStruct *)sourceImage.gdImageStructPtr;
DLLImports.gdImageStruct *pStructDest = (DLLImports.gdImageStruct *)destinationImage.gdImageStructPtr;
//loop through the source image
for (int y = 0; y < sourceImage.HeightInPixels; y++)
{
for (int x = 0; x < sourceImage.WidthInPixels; x++)
{
//ignores what falls outside the bounds of dsetination image
if ((y + yOffset) >= destinationImage.HeightInPixels || (x + xOffset) >= destinationImage.WidthInPixels)
{
continue;
}
int sourceColor = pStructSource->tpixels[y][x];
int alpha = (sourceColor >> 24) & 0xff;
//should not have 127 as magic
if (alpha == 127)
{
continue;
}
int destColor = pStructDest->tpixels[y + yOffset][x + xOffset];
int blendedColor = DLLImports.gdAlphaBlend(destColor, sourceColor);
pStructDest->tpixels[y + yOffset][x + xOffset] = blendedColor;
}
}
}
}
