Legacy ImageMagick Discussions Archive

Code: Select all

/*	
	Use either MagickMatteFloodfillImage or MagickPaintTransparentImage
	to make all the selected pixels transparent and write as a png.
*/
#include <windows.h>
#include <wand/magick_wand.h>

void test_wand(void)
{
	// If flood is non-zero use FloodFill, otherwise use PaintTransparent
	int flood = 0;
	MagickWand *magick_wand = NULL;
	// Set default fuzz to zero (see below)
	double fuzz = 0.;

	MagickWandGenesis();

	magick_wand = NewMagickWand();
	MagickReadImage(magick_wand,"eqn9_rings_040.jpg");
	MagickStripImage(magick_wand);
// Both Floodfill and PaintTransparent force the matte on so if you start with
// a JPG (for example) you don't need to force the matte on.

// In order to change the selected pixels to be fully transparent I had to set
// the "opacity" argument to 255 which means fully opaque not fully transparent.
// This was true for both MagickMatteFloodfillImage and MagickPaintTransparentImage

	// I've set the fuzz to 20 for my image but you can change or remove 
	// this as needed
	fuzz = 20.;

// A Floodfill only affects pixels in one contiguous area
	// Flood the area that is contiguous with coordinate (50,0) and has the
	// same colour to within the fuzz factor
	// In this case I know that the coordinate is black and I want that one
	// contiguous area filled with transparency
	// MagickBooleanType MagickMatteFloodfillImage(MagickWand *wand,
	//		const Quantum opacity,const double fuzz,const PixelWand *bordercolor,
	//		const long x,const long y)
	if(flood)MagickMatteFloodfillImage(magick_wand,255,fuzz,NULL,50,0);
	else {
		PixelWand *target;
		target = NewPixelWand();
		PixelSetColor(target,"black");

// A PaintTransparent affects all pixels of a given colour
		// This specifically targets all pixels having the colour specified
		// by the "target" wand and changes their opacity to the specified
		// value - EXCEPT that I had to specify an opacity of 255 to get
		// full transparency
		//		MagickBooleanType MagickPaintTransparentImage(MagickWand *wand,
		//				const PixelWand *target,const Quantum opacity,
		//				const double fuzz)
		MagickPaintTransparentImage(magick_wand,target,255,fuzz);

		DestroyPixelWand(target);
	}
	MagickWriteImage(magick_wand,"eqn9_trans_040.png");
	/* Clean up */
	if(magick_wand)magick_wand = DestroyMagickWand(magick_wand);
	MagickWandTerminus();
}

Pete

Code: Select all

	MagickWandGenesis();
	magick_wand = NewMagickWand();
	MagickReadImage(magick_wand,"input.tga");
	MagickWriteImage(magick_wand,"output.png");
	/* Clean up */
	if(magick_wand)magick_wand = DestroyMagickWand(magick_wand);
	MagickWandTerminus();