Basic help to get mestarted

[rray]

I am a long time C programmer but a MagickWand virgin.
Are there man pages for api functions?
"composite -depth 8 -dissolve 15 -gravity center stamp.png source.png destination.png"
Could someone give me a bit of starter code that would accomplish this using MagickWand?

[el_supremo]

The code below should do what you want. It uses a method described by Anthony near the end of this topic

Also see the examples at the URL in my sig.

Pete

Code: Select all

#include <windows.h>
#include <wand/magick_wand.h>

void test_wand(LPTSTR lpCmdLine)
{
	MagickWand *magick_wand = NULL,*sig_wand = NULL;
	// dimensions of source image
	long sw,sh;
	// dimensions of stamp (signature) image
	long tw,th;

	/* 
		For detailed info about MagickWand functions and their parameters see:
		http://studio.imagemagick.org/script/magick-wand.php
	*/

	MagickWandGenesis();

	magick_wand = NewMagickWand();
	// Read the image
	MagickReadImage(magick_wand,"source.png");
	// Get the dimensions of the image
	sw = MagickGetImageWidth(magick_wand);
	sh = MagickGetImageHeight(magick_wand);
	// Strip any profiles, thumbnails etc.
	MagickStripImage(magick_wand);
	MagickSetImageMatte(magick_wand,1);

	// read the stamp (signature) image
	sig_wand = NewMagickWand();
	MagickReadImage(sig_wand,"stamp.png");
	tw = MagickGetImageWidth(sig_wand);
	th = MagickGetImageHeight(sig_wand);
	MagickStripImage(sig_wand);

	// Set the sig file's opacity to 15%
	MagickEvaluateImageChannel(sig_wand,AlphaChannel,MultiplyEvaluateOperator,0.15);
	// do the Over composite operation and place the stamp image in the centre of the source
	MagickCompositeImage(magick_wand,sig_wand,OverCompositeOp,(sw-tw)/2,(sh-th)/2);
	// Set the depth to 8
	MagickSetImageDepth(magick_wand,8);
	// Write the image 
	MagickWriteImage(magick_wand,"destination.png");

	/* Clean up */
	if(magick_wand)magick_wand = DestroyMagickWand(magick_wand);
	if(sig_wand)sig_wand = DestroyMagickWand(sig_wand);
	
	MagickWandTerminus();
}

[rray]

Very nice examples
This should get me started
I do miss the man pages
Thanks

[rray]

I think the documentation needs a bit of clarification
Your code has " MagickEvaluateImageChannel(sig_wand,AlphaChannel,MultiplyEvaluateOperator,0.15);"
Four arguments

The documentation at "http://imagemagick.org/api/magick-image.php" says
MagickBooleanType MagickEvaluateImageChannel(MagickWand *wand, const MagickEvaluateOperator op,const double value)
Three arguments

I would have never figured this out without your code for reference

Richard

[el_supremo]

Yes, there's a documentation error in both MagickEvaluateImageChannel and MagickFunctionImageChannel. Neither function describes that it requires a Channel argument.

Pete

[anthony]

Report it as a bug if the documentation is wrong. Better yet provide replacement text that can be just copy and pasted into place.