On 10/2/24 9:11 AM, Louis Chauvet wrote: > 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 :-) The one reference that I found to that notation was to a French author. > > 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. Yes, thanks.
