Maintain aspect ratio option for image-save UI

[olibclarke@…]

The following bug report has been submitted:
Platform:        Darwin-18.6.0-x86_64-i386-64bit
ChimeraX Version: 0.9 (2019-06-05)
Description
Request: "Maintain current aspect ratio" checkbox in Image Save dialog - this is something I really miss from Chimera. Often I'll want to save a higher res version of an image, and having to change both the width and height proportionally is fiddly. Would be great to have this back.

Log:
> camera ortho

> cofr centerOfView

> alias crosshairs_on cofr centerofview showpivot 10,0.3

> alias crosshairs_off cofr centerofview showpivot false

UCSF ChimeraX version: 0.9 (2019-06-05)  
© 2016-2019 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> help alias

> alias ^rainbow_ryb rainbow $1
"#2F7AB4","#ACD9E8","#FFFFC2","#FCAF68","#D62328"

> open
/Users/oliverclarke/Dropbox/last_frame_rsr_ligands_real_space_refined_ss_annotated.pdb

Chain information for
last_frame_rsr_ligands_real_space_refined_ss_annotated.pdb #1  
---  
Chain | Description  
A B G I | No description available  
C D E K | No description available  
F H J O | No description available  
  

Unknown command: rainbow_ryb  

Unknown command: rainbow_ryb chain  

> alias rainbow_ryb rainbow $1
"#2F7AB4","#ACD9E8","#FFFFC2","#FCAF68","#D62328"

> rainbow_ryb chain

Expected a keyword  

> rainbow_ryb chains

Expected a keyword  

> help rainbow

Expected one of 'chains', 'polymers', 'residues', or 'structures' or a keyword  

Expected a keyword  

> rainbow chains palette rdylbu-5

> rainbow palette rdylbu-5

> rainbow palette rdylbu-5

Fetching compressed palette BuYlRd-5 from
http://www.colourlovers.com/api/palettes?keywords=BuYlRd-5&format=json&numResults=100  
Could not find palette BuYlRd-5 at COLOURlovers.com using keyword search  

> rainbow palette rdylbu-5

> volume selMaps appearance initial

No volumes specified  
No volumes specified  

> volume selMaps appearance CT_Skin

No volumes specified  
No volumes specified  

> lighting full

> lighting soft

> help rainbow

> rainbow palette #2c7bb6:#abd9e9:#ffffbf:#fdae61:#d7191c

> save image /Users/oliverclarke/Desktop/test.png width 1817 height 1207
supersample 4

> save image /Users/oliverclarke/Desktop/test.png width 1817 height 2000
supersample 4

> save image /Users/oliverclarke/Desktop/test.png width 2 height 1207
supersample 4

> save image /Users/oliverclarke/Desktop/test.png width 3000 height 1207
supersample 4




OpenGL version: 4.1 ATI-2.9.26
OpenGL renderer: AMD Radeon Pro 580 OpenGL Engine
OpenGL vendor: ATI Technologies Inc.

[Tom Goddard]

Should add a "Keep aspect ratio" checkbutton to the Save File dialog when Image format chosen. Then if the width or height is typed in the other dimension automatically changes to keep the aspect ratio. I think this option should be on by default.

[Tom Goddard]

Done.