SH7205 Datasheet, PDF (1445/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 26 2D Graphics Engine (2DG)
For the output plane, since its source character and graphics planes are both non-premultiplied, it
follows that Mf = αm, Cf = Cm, Mb = αz, and Cb = Cz. Given αRGB444 as the image format, it
follows that C(i) = 0. Therefore, by applying the algorithms for Cpout and Apout to the output
plane, we obtain:
Cgout = αm * Cm + (1 − αm) * αz * Cz
αgout = 1 − (1 − αm) * (1 − αz)
Also, for the synthetic output, which is the final output, given that the source output image plane is
premultiplied and the moving picture plane is non-premultiplied, it follows that Mb = αv = 1.
Therefore, by applying the algorithm for Cpout to the synthetic output, we obtain:
Cp = 1 * Cgout + (1 − αgout) * 1 * Cv
The following is an example where priority is given to character display (the case where the α
value assigned to the character = 1). In this case, since αm = 1, the blending of the color value of
the character part and the α value will result in the following:
Cgout = Cm, αgout = 1
In the final output, the character part will be:
Cp = Cm (no moving pictures blended)
Consequently, only characters are displayed in the results of output synthesis.
If 1 is assigned as α value (αz = 1) of the graphics plane to give priority to graphics plane display,
since the front most plane is a character plane, the results of the blending will be as follows,
consisting of a blending between characters and graphics, unless the α value of the character plane
= 0 (αm = 0):
Cgout = αmCm + (1 − αm) Cz, αgout = 1
The final output will be:
Cp = αmCm + (1 − αm) Cz (no moving pictures blended)
Rev. 1.00 Mar. 25, 2008 Page 1413 of 1868
REJ09B0372-0100