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Diffstat (limited to 'src/smi.h')
| -rw-r--r-- | src/smi.h | 36 |
1 files changed, 36 insertions, 0 deletions
@@ -72,6 +72,42 @@ authorization from the XFree86 Project and Silicon Motion. #define SMI_USE_VIDEO 1 #define SMI_USE_CAPTURE 1 +/* + * Leaving attempt implementation of an argb cursor using alpha plane + * for the smi 501/502 under this ifdef for now. Maybe it will be fixed + * in a subsequent hardware revision. + * The problem is that the alpha plane will only work (that is, become + * visible) if alpha_plane_tl is set to top:=0 and left:=0. + * Also, if alpha_plane_br does not match panel dimensions, the alpha + * plane will be displayed tilled in the "first" row, with corruption on + * on all odd columns. + * Since setting the alpha fb_address works, to implement an argb cursor + * using the alpha plane, with the current hardware bugs, it would be + * required to: + * o allocate an offscreen area of pSmi->lcdWidth * pSmi->lcdHeight * 2 + * o set statically tl/tr to 0,0,pSmi->lcdWidth-1,pSmi->lcdHeight-1 + * o use alpha format 3 (argb 4:4:4:4), or alternatively format 1 + * (rgb 5:6:5), and in the last case, a global 50% alpha is the + * best bet, and for the argb cursors being used at the time of this + * writing, they look correct, while 100% opaque looks wrong. + * o when positioning the pointer, first erase it from the offscreen + * area, then repaint it at the proper offset in the alpha offscreen + * area. + * .... argb software cursor works way better + * (There are some other alternatives, like using 8 bits indexed mode, + * but when using a global alpha value, instead of per pixel, most argb + * cursors will not look correctly, regardless of the alpha value, that + * should be from 50 to 100% transparency). + * But still there would be the problem of memory requiring a 128 bit + * alignment, what would require either moving the image in the memory, + * and/or some trick with the vsync pixel panning. + * + * Until the alpha layer is corrected in some newer revision (or removed?), + * it could be used as something like an alternate crt, that happens to be + * on top of the panel (and has 16 transparency levels). + */ +#define SMI_CURSOR_ALPHA_PLANE 0 + /******************************************************************************/ /* S T R U C T U R E S */ /******************************************************************************/ |