Re: [Scilab-users] {EXT} Fwd: plotting dots vs xfarc
Hi, I think I'll modify the pixels in the imagelike: img(x,y) = 255; If necessary I will also change some neighboured pixels to enlarge the "dot"-size. I do not need them blue...this was just to demonstrate that plot(x,y,'o') ( = white) and xfarc(x_arc,y_arc, w_arc,h_arc,0,360*64) (= blue) do not always plot at the same locationeven all coordinates are just simple integers. So far I could see, this does not change, even if one changes the pixel_drawing_mode attribute. Thanks for your ideas, Philipp Am Do., 1. Okt. 2020 um 10:25 Uhr schrieb Antoine Monmayrant < antoine.monmayr...@laas.fr>: > > On 01/10/2020 09:05, Dang Ngoc Chan, Christophe wrote: > > Hello, > > > >> De la part de P M > >> Envoyé : mercredi 30 septembre 2020 16:50 > >> > >> exact dot-coordinates, drawn as filled circles. > >> All pixel coordinates of such an area would have to have exactly one > single pixel value. > >> The resulting graphic right now is stored via: xs2bmp. > >> [...] > >> - It seems that the resulting pixels of the dot in the final image are > not equally colored. > > I suspect the following thing: pixels are squares, not dots. > > > > So it may be that xs2bmp somehow inter-/extrapolate the colours. > > You then have a "leak" between the coloured pixel and its neighbours. > > > > You may try to draw squares of the exact size of the final pixel (e.g. > 1/320 width and 1/200 height of the graphical window for a 320 × 200 raster > picture). > > > > You may also try some functions from the image processing toolboxes. > Well, another approach would be to: > - use Matplot to display your image as a matrix, let's say [0:255] range. > - modify the data in the matrix to be displayed where you went to get > your "dot": like your change your data to 256 > - use a colormap that is grayscale from [0:255] and has a fancy color > for 256 (blue?). > > If you do this, you should get a perfect co-registration of your image > and your "overlayed" markers. > Of course, your markers will not be circular dots, just a single pixel > with what I described above, but you can also generate your own shapes > (bigger squares, crosses, ~circles), provided that you use an odd number > of pixels. > > Hope it helps, > > Antoine > > > > > Hope this helps > > > > Regards > > > > -- > > Christophe Dang Ngoc Chan > > cd...@wanadoo.fr > > > > General > > This e-mail may contain confidential and/or privileged information. If > you are not the intended recipient (or have received this e-mail in error), > please notify the sender immediately and destroy this e-mail. Any > unauthorized copying, disclosure or distribution of the material in this > e-mail is strictly forbidden. > > ___ > > users mailing list > > users@lists.scilab.org > > http://lists.scilab.org/mailman/listinfo/users > > > ___ > users mailing list > users@lists.scilab.org > http://lists.scilab.org/mailman/listinfo/users > ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] {EXT} Fwd: plotting dots vs xfarc
On 01/10/2020 09:05, Dang Ngoc Chan, Christophe wrote: Hello, De la part de P M Envoyé : mercredi 30 septembre 2020 16:50 exact dot-coordinates, drawn as filled circles. All pixel coordinates of such an area would have to have exactly one single pixel value. The resulting graphic right now is stored via: xs2bmp. [...] - It seems that the resulting pixels of the dot in the final image are not equally colored. I suspect the following thing: pixels are squares, not dots. So it may be that xs2bmp somehow inter-/extrapolate the colours. You then have a "leak" between the coloured pixel and its neighbours. You may try to draw squares of the exact size of the final pixel (e.g. 1/320 width and 1/200 height of the graphical window for a 320 × 200 raster picture). You may also try some functions from the image processing toolboxes. Well, another approach would be to: - use Matplot to display your image as a matrix, let's say [0:255] range. - modify the data in the matrix to be displayed where you went to get your "dot": like your change your data to 256 - use a colormap that is grayscale from [0:255] and has a fancy color for 256 (blue?). If you do this, you should get a perfect co-registration of your image and your "overlayed" markers. Of course, your markers will not be circular dots, just a single pixel with what I described above, but you can also generate your own shapes (bigger squares, crosses, ~circles), provided that you use an odd number of pixels. Hope it helps, Antoine Hope this helps Regards -- Christophe Dang Ngoc Chan cd...@wanadoo.fr General This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error), please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden. ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] {EXT} Fwd: plotting dots vs xfarc
Hello, > De la part de P M > Envoyé : mercredi 30 septembre 2020 16:50 > > exact dot-coordinates, drawn as filled circles. > All pixel coordinates of such an area would have to have exactly one single > pixel value. > The resulting graphic right now is stored via: xs2bmp. > [...] > - It seems that the resulting pixels of the dot in the final image are not > equally colored. I suspect the following thing: pixels are squares, not dots. So it may be that xs2bmp somehow inter-/extrapolate the colours. You then have a "leak" between the coloured pixel and its neighbours. You may try to draw squares of the exact size of the final pixel (e.g. 1/320 width and 1/200 height of the graphical window for a 320 × 200 raster picture). You may also try some functions from the image processing toolboxes. Hope this helps Regards -- Christophe Dang Ngoc Chan cd...@wanadoo.fr General This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error), please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden. ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
