how to call MagickVignetteImage ?

[hytgbn]

I'm looking for vignette effects like adobe photoshop.

I found MagickVignetteImage function, which have 4 arguments.

But It always give me eclipsed image with white border.

I want to get black vignetted image.

How can I call MagickVignette image ? or FxImage?

[fmw42]

set the background color

[el_supremo]

Try incorporating this code segment into your program:

Code: Select all

	MagickWand *m_wand = NULL;
	PixelWand *p_wand = NULL;
	long w,h;

	MagickWandGenesis();

	m_wand = NewMagickWand();

        // Change the filename here
	MagickReadImage(m_wand,"chsp.jpg");

	w = MagickGetImageWidth(m_wand);
	h = MagickGetImageHeight(m_wand);

	p_wand = NewPixelWand();
	PixelSetColor(p_wand,"black");
	MagickSetImageBackgroundColor(m_wand,p_wand);
	MagickVignetteImage(m_wand,0,175,(long)(w*.05),(long)(h*.05));

The default background colour is white but you can change it as shown above.
You'll have to play with the size of the ellipse and the black and white points to get the effect you want.

Pete

[hytgbn]

el_supremo // Thank you so much

Now I can change background color.

but I have one more question..


What do black point and white point mean?

I changed them but the result isn't change at all.




this is the result image, it doesn't have alpha effect.

So... what do I have to check?

magick wand is created by function MagickConstituteImage

MagickConstituteImage(magick_wand, width, height, "ARGB", CharPixel, bytes);

[el_supremo]

What do black point and white point mean?

I haven't figured out exactly what their effect is on the image.

this is the result image, it doesn't have alpha effect.

Your image doesn't show up at all and I also can't download it.

Pete

[hytgbn]

oops I'm sorry

this is url of image . http://www.twitpic.com/1aflvq

it doesn't effect by black point and white point arguments.

[AidenMontgomery]

I know this is an old thread, but for anyone else finding it whilst searching.

What do black point and white point mean?

I haven't figured out exactly what their effect is on the image.

this is the result image, it doesn't have alpha effect.

What I have figured out is that the black and white point values affect the feathering of the vignette effect.
So black = 0 and white = 255 gives a nice feathered/blended look, whereas black = 0 and white = 0 gives no feathering.

The following code gives me a nice blended vignette effect.

Code: Select all

   MagickWand *m_wand = NULL;
   PixelWand *p_wand = NULL;
   long w,h;

   MagickWandGenesis();

   m_wand = NewMagickWand();

        // Change the filename here
   MagickReadImage(m_wand,"chsp.jpg");

   w = MagickGetImageWidth(m_wand);
   h = MagickGetImageHeight(m_wand);

   p_wand = NewPixelWand();
   PixelSetColor(p_wand,"black");
   MagickSetImageBackgroundColor(m_wand,p_wand);
   MagickVignetteImage(m_wand,0,255,(long)(w*.05),(long)(h*.05));