topic ippiAlphaComp (Alpha Composition) in Intel® Integrated Performance Primitives

ippiAlphaComp (Alpha Composition)

reportbase — Fri, 04 Dec 2009 07:15:28 GMT

ippiAlphaCompC_8u_ works great for a constant alpha.

However, I need to pass in an array of alphas, not a single alpha

Any ideas?. Heres the existing function:

ippiAlphaCompC_8u_AC4R,
( const Ipp8u* pSrc1, int src1Step,
Ipp8u alpha1,
const Ipp8u* pSrc2, int src2Step,
Ipp8u alpha2,
Ipp8u* pDst, int dstStep,
IppiSize roiSize,
IppiAlphaType alphaType ))

I need something like this:

ippiAlphaCompC_8u_AC4R_modified,
( const Ipp8u* pSrc1, int src1Step,
const Ipp8u* pSrc2, int src2Step,
Ipp8u* pDst, int dstStep,
Ipp8u* pAlpha,
IppiSize roiSize,
IppiAlphaType alphaType ))

The first buffer (pSrc1) would be composed against the alpha value.

The second buffer (pSrc2) would be composed against the inverse of that alpha value.

(pDst) would get the result.
(pAlpha) would be the array of alphas.

Re: ippiAlphaComp (Alpha Composition)

Chao_Y_Intel — Fri, 04 Dec 2009 07:59:42 GMT

Hello,

How does AlphaComp_8u function work for you there? This function will use alpha values of
each pixel to combine images.

Thanks,
Chao

Re: ippiAlphaComp (Alpha Composition)

reportbase — Fri, 04 Dec 2009 10:02:32 GMT

Quoting - Chao Y (Intel)

Hello,

How does AlphaComp_8u function work for you there? This function will use alpha values of
each pixel to combine images.

Thanks,
Chao

That one does not work either for a different reason.

It combines two rgba images, using the alpha values of each pixel, and interpolates the results.

I'm trying to render a font glyph, which has the following inputs:

1) grayscale image of the font glyph, which is just an array of unsigned char(s).
2) Color of the font glyph, which is just an rgb. (int)
3) The background image. Just an array of rgb(s).

I want to insert the font glyph onto the background.

Re: ippiAlphaComp (Alpha Composition)

reportbase — Tue, 08 Dec 2009 00:12:53 GMT

Perhaps I should switch the question to a featuer request. It would appear to me to be only a small modification to the existing api. How would I go about doing that?

Re: ippiAlphaComp (Alpha Composition)

Chao_Y_Intel — Mon, 14 Dec 2009 02:53:45 GMT

Hi,

Thanks for letting us know. I tracked this request for future consideration.

Regards,
Chao