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IDProjectCategoryView StatusLast Update
0002251SkyChart1-Softwarepublic19-12-29 11:30
ReporterMattia Verga Assigned ToPatrick Chevalley  
PrioritylowSeverityfeatureReproducibilityN/A
Status assignedResolutionopen 
Target Version4.4 
Summary0002251: Create blurred surface outlines catalogs with catgen
DescriptionWhile creating new nebulae outlines for OpenNGC, I thought it would be nice to have outlines at different brightness level to create surfaces catalogs with Catgen.

However, actually catgen generated surfaces display on top of object markers: see Chart_3.png. It would be nice if those surfaces could be rendered transparently and, maybe, with blurred borders. I made a couple of mockups in Gimp to show that: I've simply put the different outlines on three separate levels, each one with an opacity set to 10%, and blurred the selection before fill them.

What I cannot mockup, is that the object markers should be rendered on a higher layer than the nebulae, with an appropriate transparency.

I'm also uploading the catalog files (outlines and surfaces) used to generate the Chart_1.png and Chart_3.png. (those catalogs aren't completed yet).
TagsNo tags attached.

Activities

Mattia Verga

19-12-26 18:30

reporter  

blurred_with_outlines.png (274,816 bytes)   
blurred_with_outlines.png (274,816 bytes)   
blurred_without_outlines.png (193,432 bytes)   
blurred_without_outlines.png (193,432 bytes)   
Chart_1.png (163,017 bytes)   
Chart_1.png (163,017 bytes)   
catalogs.zip (145,101 bytes)
Chart_3.png (107,653 bytes)   
Chart_3.png (107,653 bytes)   

Patrick Chevalley

19-12-27 11:12

administrator   ~0006168

This multi-level surface nebula look very good!

I make a quick test to draw the surface with transparency to see the catalog objects below and for me this look good, see screenshot.
The transparency parameters can be adjusted, for now I set alpha to 128 and linear blend.

I also test with blurred surface but I cannot say I like it.

The brown background on your screenshot is because of the negative elevation and the option to fill the ground with brown color. Maybe it is better to test in equatorial view.

I think a good way to implement that is to add a alpha parameter in Catgen, with 255 as the default value for compatibility.
Probably a global parameter (not by object) is sufficient?
with_transparency.png (144,440 bytes)   
with_transparency.png (144,440 bytes)   

Patrick Chevalley

19-12-27 13:20

administrator   ~0006169

One more test, with alpha transparency set to 100 and changing the darkest color to #3C3C3C in Catgen.
with_transparency100.png (142,976 bytes)   
with_transparency100.png (142,976 bytes)   

Patrick Chevalley

19-12-27 13:50

administrator   ~0006170

Here the test with blurred surface using a 10 pixel radius, with and without the additional lines.
I still have a tendency to prefer the clean aspect of the non-blurred surface.

Patrick Chevalley

19-12-27 13:55

administrator   ~0006171

Replacing the previous screenshot because I wrongly use a gamma corrected transparent blend and it must be linear.
blurred10+lines.png (215,841 bytes)   
blurred10+lines.png (215,841 bytes)   
blurred10.png (187,445 bytes)   
blurred10.png (187,445 bytes)   

Mattia Verga

19-12-27 17:45

reporter   ~0006172

It looks really good!
Yes, I think a global alpha parameter should be fine. About the blurred / non-blurred, I have no preferences: I think that would require to add another parameter in Catgen, so if you don't want to bloat Catgen interface with a thousand options, the non-blurred version it's fine.

One thing I think it could be enhanced is the drawing of object markers: it seems they're rendered below the nebulae, so they're not really clearly visible. I think the correct layer sequence should be background - nebulae - markers - stars and text and give markers fill color an high alpha (say 200).
In fact, currently using the graphic mode for the milky way, markers prevent that to show, as in the attached screenshot.
milky.png (199,652 bytes)   
milky.png (199,652 bytes)   

Mattia Verga

19-12-28 15:28

reporter   ~0006175

I've just realized that surface boundaries are not spline, but plain lines... in that case a blurred boundary could be a solution to better match the spline outlines; another solution would be to increase the shape precision with much more points and a bigger catalog file.
smooth.png (183,294 bytes)   
smooth.png (183,294 bytes)   

Patrick Chevalley

19-12-28 20:38

administrator   ~0006176

Mattia,

Maybe it is best to let the user configure the transparency level and if it want blurred surface or not. I can add this two options in the catalog or display settings.
Probably no one will change this setting if this require to run catgen.

It is easy to fix the surface to use spline, I just have to change one call to the graphic library. I do it now.

Drawing order is sometime difficult, specifically if there is no transparency. But transparency can make some area more confuse.
For example if I draw the nebula before the milkyway no more nebula are visible, all hidden by the milkyway.
I also have different order for screen and printer.

I try to finish this changes to make then available for testing.

Patrick Chevalley

19-12-28 21:40

administrator   ~0006177

I commit the change:
https://github.com/pchev/skychart/commit/e6033acb2c4c07903af871b52e8e35233b589f11

The two new options are in Setup / Display, next to the nebula drawing option.
By default it use no blur and transparency=100.

Tell me how it look for you with different transparency.

I will make the two option to look better next week because now I work remotely with strange screen resolution that make the widget alignment not easy.

Mattia Verga

19-12-29 11:29

reporter   ~0006178

Hi Patrick,
the two options looks quite fine, there's a small glitch in the right border alignment, but overall this s getting nicer and nicer!

I've also testes how it looks in line mode and on printer, there are two issues here:
- in line mode splines are draw as normal lines.
- on printer color line mode, surfaces borders are black (they doesn't respect the color on screen).
graphic_mode.png (169,755 bytes)   
graphic_mode.png (169,755 bytes)   
line_mode.png (213,249 bytes)   
line_mode.png (213,249 bytes)   

Mattia Verga

19-12-29 11:30

reporter  

print.zip (153,468 bytes)

Issue History

Date Modified Username Field Change
19-12-26 18:30 Mattia Verga New Issue
19-12-26 18:30 Mattia Verga File Added: blurred_with_outlines.png
19-12-26 18:30 Mattia Verga File Added: blurred_without_outlines.png
19-12-26 18:30 Mattia Verga File Added: Chart_1.png
19-12-26 18:30 Mattia Verga File Added: catalogs.zip
19-12-26 18:30 Mattia Verga File Added: Chart_3.png
19-12-27 11:12 Patrick Chevalley File Added: with_transparency.png
19-12-27 11:12 Patrick Chevalley Note Added: 0006168
19-12-27 11:14 Patrick Chevalley Assigned To => Patrick Chevalley
19-12-27 11:14 Patrick Chevalley Status new => feedback
19-12-27 11:14 Patrick Chevalley Target Version => 4.4
19-12-27 13:20 Patrick Chevalley File Added: with_transparency100.png
19-12-27 13:20 Patrick Chevalley Note Added: 0006169
19-12-27 13:50 Patrick Chevalley File Added: blurred10+lines.png
19-12-27 13:50 Patrick Chevalley File Added: blurred10.png
19-12-27 13:50 Patrick Chevalley Note Added: 0006170
19-12-27 13:54 Patrick Chevalley File Deleted: blurred10.png
19-12-27 13:54 Patrick Chevalley File Deleted: blurred10+lines.png
19-12-27 13:55 Patrick Chevalley File Added: blurred10+lines.png
19-12-27 13:55 Patrick Chevalley File Added: blurred10.png
19-12-27 13:55 Patrick Chevalley Note Added: 0006171
19-12-27 17:45 Mattia Verga File Added: milky.png
19-12-27 17:45 Mattia Verga Note Added: 0006172
19-12-27 17:45 Mattia Verga Status feedback => assigned
19-12-28 15:28 Mattia Verga File Added: smooth.png
19-12-28 15:28 Mattia Verga Note Added: 0006175
19-12-28 20:38 Patrick Chevalley Note Added: 0006176
19-12-28 21:40 Patrick Chevalley Note Added: 0006177
19-12-29 11:29 Mattia Verga File Added: graphic_mode.png
19-12-29 11:29 Mattia Verga File Added: line_mode.png
19-12-29 11:29 Mattia Verga Note Added: 0006178
19-12-29 11:30 Mattia Verga File Added: print.zip