вс, 2 окт. 2022 г., 04:27 Phyllis Smith <[email protected]>:
> > more documentation, it seems Adobe products use shared code for this .... >> >> >> https://www.rippletraining.com/blog/final-cut-pro-x/understanding-blend-modes-final-cut-pro/ >> > Using the above URL for comparison, I used it on current CinGG and HV > 4.6.1 for subtract. HV matches and GG does not. So tomorrow I will look > at the code that Andrew quoted below to see if adding the specific guard > corrects the issue. In the attached, top left is HV 4.6.1 and bottom left > is GG current with right side the URL. > you forgot attach? >> >> --quote--- >> >> Subtract >> >> Subtract does what it advertises; the color values of one layer are >> subtracted from the other layer. This tends to have a net darkening effect. >> Pixel values can’t fall below zero, so negative numbers are rendered to >> black. >> >> >> ---end quote--- >> >> >> in older cingg code (from 4.6.mod era - earliest public code on Google >> code) I see such construct : >> >> >> /data/data/com.termux/files/home/cingg-g~nelerra-4.6.mod/cinelerra/overlayframe.C >> 4762/69317 UTF-8 6% >> >> break; \ >> >> case TRANSFER_SUBTRACT: \ >> >> r = (temp_type)output[0] - (temp_type)input1; \ >> >> g = ((temp_type)output[1] - >> (temp_type)chroma_offset) - \ >> >> ((temp_type)input2 - >> (temp_type)chroma_offset) + \ >> >> (temp_type)chroma_offset; \ >> >> b = ((temp_type)output[2] - >> (temp_type)chroma_offset) - \ >> >> ((temp_type)input3 - >> (temp_type)chroma_offset) + \ >> >> (temp_type)chroma_offset; \ >> >> if(r < 0) r = 0; \ >> >> if(g < 0) g = 0; \ >> >> if(b < 0) b = 0; \ >> >> r = (r * opacity + output[0] * transparency) / >> max; \ >> >> g = (g * opacity + output[1] * transparency) / >> max; \ >> >> b = (b * opacity + output[2] * transparency) / >> max; \ break; \ >> >> >> --- >> >> >> so it basically had specific guard against going negative. Not sure if >> our implementation does the same just in different place? >> >> >> I see no specific handling of it in macros ... >> >> >> >> overlayframe.h [----] 38 L:[ 53+ 0 53/615] *(1572/17155b) 001[*][X] >> >> // ADDITION<--->[(Sa + Da), (Sc + Dc)] >> >> #define ALPHA_ADDITION(mx, Sa, Da) (Sa + Da) >> >> #define COLOR_ADDITION(mx, Sc, Sa, Dc, Da) (Sc + Dc) >> >> #define CHROMA_ADDITION COLOR_ADDITION >> >> >> // SUBTRACT<--->[(Sa - Da), (Sc - Dc)] >> >> #define ALPHA_SUBTRACT(mx, Sa, Da) (Sa - Da) >> >> #define COLOR_SUBTRACT(mx, Sc, Sa, Dc, Da) (Sc - Dc) >> >> #define CHROMA_SUBTRACT COLOR_SUBTRACT >> >> >> but apparently you can add some comparing here ...just .. it went from >> two-stage process to single stage for untrained eye and I am not sure where >> to put those ifs? >> >> >> >> >> >> >>> >>> вс, 25 сент. 2022 г., 11:06 Andrew Randrianasulu < >>> [email protected]>: >>> >>>> I found Graphics-softlight mode behaving visually close...but not sure >>>> how close to CinHV/CV subtract mode ... >>>> >>>> >>>> >>>> вс, 25 сент. 2022 г., 10:24 Andrew Randrianasulu < >>>> [email protected]>: >>>> >>>>> I was trying to repeat tuto at >>>>> >>>>> https://linuxvideoediting.blogspot.com/2022/01/transparent-text-effect-in-Cinelerra-part1.html?m=1 >>>>> >>>>> >>>>> so I loaded video, created empty new vid track, applied 'titles', >>>>> 'blur' and 'invert video' to _empty track_, then set track's mode to >>>>> subtract .... result was color inversion of original video on second vid >>>>> track ( >>>>> >>>>
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