re xv problems in article rohjc avt cc tut fi jk lehtori cc tut fi kouhia juhana writes in article apr nessie mcc ac uk c c lilley mcc ac uk writes moved on a bit i wrote something about making color modifications quickly with bit quantized images and only at the saving the image to file process we have to make the modifications to the bit image this makes sense because the main use of xv is only viewing images doing many changes to image we should keep all modifications in a buffer and then before making the operations to bit image we should simplify the operation list for unnecessary operations think about what you are saying here the bit image is quantised down to bits so many similar colours are mapped onto a single palette colour this colour gets modified in fairly arbitrary ways you then want to apply these modifications back to the bit file so you have to find which colours mapped to this one palette colour ok you could do this by copying the bit file to a bit file and using the extra bits to hold the index entry having done this you need to do something to them what exactly apply the difference in rgb between the original and modified palette entry to each colour in the group this could generate colours with rgb outside the range it would also lead to discontinuities when different parts of a smooth colour gradient mapped to several different palette entries you could interpolate from full modification to no modification depending how far each colour was from the palette entry however i suspect this would look rather odd so in summary what i said in my previous posting still holds how would you suggest doing colour editing on a bit file how would you group related colours to edit them together only global changes could be done unless the software were very different and much more complicated if you want to do colour editing on a bit image you need much more powerfull software which is readily available commercially in other words to edit a bit file you need software built for the job tacking mods onto xv is going to create more problems than it solves as to the other bits you seemed to be claiming that there were bugs in xv if that was not what you meant then you propably misunderstood what i wrote as you have done in many places so far yes i probably did i found that the collected digest format of your posting made it a little difficult to understand precisely what your point was sorry if i misunderstood you also missed what is were wrong with xv however i did wrote it yes again what is was wrong with xv chris lilley technical author itti computer graphics and visualisation training project computer graphics unit manchester computing centre oxford road manchester uk m pl internet c c lilley mcc ac uk voice fax janet c c lilley uk ac mcc
