On 02/10/24 - 08:49, Randy Dunlap wrote: > Hi Louis, > > On 10/2/24 1:57 AM, Louis Chauvet wrote: > > On 01/10/24 - 20:54, Randy Dunlap wrote: > >> Hi-- > >> > >> On 9/30/24 8:31 AM, Louis Chauvet wrote: > >>> The pre_mul_alpha_blend is dedicated to blending, so to avoid mixing > >>> different concepts (coordinate calculation and color management), extract > >>> the x_limit and x_dst computation outside of this helper. > >>> It also increases the maintainability by grouping the computation related > >>> to coordinates in the same place: the loop in `blend`. > >>> > >>> Reviewed-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> > >>> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx> > >>> --- > >>> drivers/gpu/drm/vkms/vkms_composer.c | 40 +++++++++++++++++------------------- > >>> 1 file changed, 19 insertions(+), 21 deletions(-) > >>> > >>> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c > >>> index 931e214b225c..4d220bbb023c 100644 > >>> --- a/drivers/gpu/drm/vkms/vkms_composer.c > >>> +++ b/drivers/gpu/drm/vkms/vkms_composer.c > >>> @@ -24,34 +24,30 @@ static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha) > >>> > >>> /** > >>> * pre_mul_alpha_blend - alpha blending equation > >>> - * @frame_info: Source framebuffer's metadata > >>> * @stage_buffer: The line with the pixels from src_plane > >>> * @output_buffer: A line buffer that receives all the blends output > >>> + * @x_start: The start offset > >>> + * @pixel_count: The number of pixels to blend > >> > >> so is this actually pixel count + 1; or > >> > >>> * > >>> - * Using the information from the `frame_info`, this blends only the > >>> - * necessary pixels from the `stage_buffer` to the `output_buffer` > >>> - * using premultiplied blend formula. > >>> + * The pixels 0..@pixel_count in stage_buffer are blended at @x_start..@x_start+@pixel_count in > >> > >> should these ranges include a "- 1"? > >> Else please explain. > > > > Hi Randy, > > > > For the next version, I will use standard mathematical notation to clarify > > the "inclusiveness" of the interval: [0;pixel_count[ > > Hm, I can read that after a second or two. > > My math classes always used: [0,pixel_count) > for that range, and that is what most of the internet says as well. I'm french, and we use ]a;b[ notation at school :-) Both are valids according to ISO80000-2, but I will change it for the next revision. > or you could just stick with > The pixels from 0 through @pixel_count - 1 in stage_buffer are blended at @x_start > through @x_start through @x_start + @pixel_count - 1. > > but after writing all of that, I think using range notation is better. I also prefer ranges, way shorter to write, and easier to understand at first sight. > thanks.
