Good morning!

I studied about the bitmap, color coponent and algorithm of my application.

I have problem about my application algorithm.

I use an UIImagePickerController class.

But this class has a few APIs, and it have no API that I want.

I'd like to a get feature that is invoked when cansel button clicked.

Thus I'll make the new method for myproblem is solved.

Next, about the bitmap, color coponent.

These needs knowledge of Quarts2D. 

I got a knowledge of premultiplied alpha value.

Use premultiplied alpha value, so speed up of render.

,,,reference say

"For bitmaps that have an alpha component, whether the color components are already multiplied by the alphavalue. Premultiplied alpha describes a source color whose components are already multiplied by an alpha value. Premultiplying speeds up the rendering of animage bye liminating an extra multiplication operation per color component. For example, inan RGB color space, rendering animage 
with premultiplied alpha eliminates three multiplication operations(red times alpha, green times alpha, 
and blue times alpha)for each pixel in the image."

Bitmap has a difficult  problem.

I studied how to change UIImage to bitmap, and change color component of pixel of  bitmap.

Today, I cold get knowledge the ,,,

size_t macro  a unsigned int.

y = (77 * r + 28 * g + 151 * b) / 256;←this code represent a brightness for human.

concept of pointer of C language.

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I'll study about the bitmap component.

And I'll prepare the attend the technical lab at wwdc2009.