<div dir="ltr"><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto">may be Phyllis can replace our original red-green square images with full-color gradients + photo, so effect will be more natural? Or add this into new appendix .....</div></div></blockquote></div></div></div></blockquote><div><span class="gmail_default" style="font-size:small">Good idea to add in appendix but I am not sure I could get it right.</span></div></div></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto">may be download images from said website via "download" button, then place them on tracks and render single frame for each of those 30 different composition modes on top track? sorry if this sounds big, I can try this idea myself, just then I will generate whole folder of images for you to pick up and integrate into manual. < oh Andrew, come on, you just too lazy for even minimal work - my conscience ></div></div></blockquote><div><span class="gmail_default" style="font-size:small"> <br></span></div><div><span class="gmail_default" style="font-size:small">It does sound big but quite interesting to me and not a problem with TeX editing. I think I will have time in October to get serious and then have you proofread?</span> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><br></div><div dir="auto">or you mean whole TeX editing? I should try to retest if my pdf generating setup still work ....</div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div><span class="gmail_default" style="font-size:small"></span><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><br></div><div dir="auto">more documentation, it seems Adobe products use shared code for this ....</div><div dir="auto"><br></div><div dir="auto"><a href="https://www.rippletraining.com/blog/final-cut-pro-x/understanding-blend-modes-final-cut-pro/" rel="noreferrer noreferrer noreferrer noreferrer" target="_blank">https://www.rippletraining.com/blog/final-cut-pro-x/understanding-blend-modes-final-cut-pro/</a></div></div></blockquote><div><span class="gmail_default" style="font-size:small">Another good URL to look at. When coding all of the Overlay modes, Porter Duff explanations and example were used as the basis. Not sure if Gimp and PhotoShop use the same basis.<br></span></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto">--quote---</div><div dir="auto"><br></div><div dir="auto"><div dir="auto"><h3 style="line-height:1.04">Subtract</h3>
</div><div dir="auto"><p>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.</p><p><br></p><p>---end quote---</p><p><br></p><p>in older cingg code (from 4.6.mod era - earliest public code on Google code) I see such construct :</p><p><br></p><p>/data/data/com.termux/files/home/cingg-g~nelerra-4.6.mod/cinelerra/overlayframe.C 4762/69317 UTF-8 6%</p><p> break; \</p><p> case TRANSFER_SUBTRACT: \</p><p> r = (temp_type)output[0] - (temp_type)input1; \</p><p> g = ((temp_type)output[1] - (temp_type)chroma_offset) - \</p><p> ((temp_type)input2 - (temp_type)chroma_offset) + \</p><p> (temp_type)chroma_offset; \</p><p> b = ((temp_type)output[2] - (temp_type)chroma_offset) - \</p><p> ((temp_type)input3 - (temp_type)chroma_offset) + \</p><p> (temp_type)chroma_offset; \</p><p> if(r < 0) r = 0; \</p><p> if(g < 0) g = 0; \</p><p> if(b < 0) b = 0; \</p><p> r = (r * opacity + output[0] * transparency) / max; \</p><p> g = (g * opacity + output[1] * transparency) / max; \</p><p> b = (b * opacity + output[2] * transparency) / max; \ break; \</p><p><br></p><p>---</p><p><br></p><p>so it basically had specific guard against going negative. Not sure if our implementation does the same just in different place?</p><p><br></p><p>I see no specific handling of it in macros ...</p><p><br></p><p><br></p><p>overlayframe.h [----] 38 L:[ 53+ 0 53/615] *(1572/17155b) 001[*][X]</p><p>// ADDITION<--->[(Sa + Da), (Sc + Dc)]</p><p>#define ALPHA_ADDITION(mx, Sa, Da) (Sa + Da)</p><p>#define COLOR_ADDITION(mx, Sc, Sa, Dc, Da) (Sc + Dc)</p><p>#define CHROMA_ADDITION COLOR_ADDITION</p><p><br></p><p>// SUBTRACT<--->[(Sa - Da), (Sc - Dc)]</p><p>#define ALPHA_SUBTRACT(mx, Sa, Da) (Sa - Da)</p><p>#define COLOR_SUBTRACT(mx, Sc, Sa, Dc, Da) (Sc - Dc)</p><p>#define CHROMA_SUBTRACT COLOR_SUBTRACT</p><p><br></p><p>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?</p><p><br></p><p><br></p><p><br></p><p><br></p></div></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">вс, 25 сент. 2022 г., 11:06 Andrew Randrianasulu <<a href="mailto:randrianasulu@gmail.com" rel="noreferrer noreferrer noreferrer noreferrer noreferrer" target="_blank">randrianasulu@gmail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">I found Graphics-softlight mode behaving visually close...but not sure how close to CinHV/CV subtract mode ...<div dir="auto"><br></div><div dir="auto"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">вс, 25 сент. 2022 г., 10:24 Andrew Randrianasulu <<a href="mailto:randrianasulu@gmail.com" rel="noreferrer noreferrer noreferrer noreferrer noreferrer noreferrer" target="_blank">randrianasulu@gmail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">I was trying to repeat tuto at<div dir="auto"><a href="https://linuxvideoediting.blogspot.com/2022/01/transparent-text-effect-in-Cinelerra-part1.html?m=1" rel="noreferrer noreferrer noreferrer noreferrer noreferrer noreferrer noreferrer noreferrer" target="_blank">https://linuxvideoediting.blogspot.com/2022/01/transparent-text-effect-in-Cinelerra-part1.html?m=1</a><br></div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto">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 (</div></div>
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