Hi Sven, Thanks very much for your reply and consideration. First of all, let me say that I think your suggestion of removing the 16:1 zoom factor limit as you have done in 1.3 is probably a good idea. In fact, I have already made the corresponding changes to my copy of gimp 1.2.4, and it seems to work well. Now, on to your my proposal and your suggested alternatives... Upon further consideration, I must agree with your concern regarding a case such as the 2000 x 399 example that you gave. However, I don't think that either of the alternatives that you suggested would work well either... I don't agree that your first suggestion (16X limit) is reasonable all by itself. Consider my typical image, 2000 x 100000 pixels. If we went with your first alternative, then the initial display of this image on my 1600 x 1200 screen would be at a 16X reduction, resulting in an image width of only 125 pixels, or just about 1.25 inches out of my available 12 inch display width. Your second alternative would produce even worse results. My delay in getting back to you on this is due to the fact that I have spent almost the whole day thinking about this problem and tinkering with various potential solutions. I finally came up with something that is fairly simple and provides reasonable results on a very wide range of image sizes and aspect ratios. The attached files provide both my algorithm (scaleImage.sas), and the results that it would produce (scaleImage.txt) for test cases covering a wide range of possibilities from 10 to 100000 pixels in 25 diffferent combinations on both axes. I actually evaluated even more cases than that, but didn't include those in the attachment because they merely made the results more voluminous to wade through. I wrote the attached algorithm in SAS to simplify my code changes while evaluating various options and to simplify reporting the results. However, this algorithm can be easily converted to C, and I will be happy to do so and provide a new patch if you agree that the results it produces are desirable. SAS is fairly straightforward as far as the code for the algorithm is concerned, so hopefully you will be able to interpret my code without any significant difficulty. The new algorithm provides a maximum of compatibility with prior behavior for typical images, while also solving the high aspect ratio problem that I initially reported. It solves the problems that you found with my previous proposal, as well as those that I found with the alternatives that you suggested. It maintains the 16 fold automatic scale reduction limit that was intended by prior versions of app/interface.c, and also addresses the 1 pixel minimum issue that you raised. I'd appreciate it if you could look all of this over and let me know if you think it is acceptable. If so, then I will recode in C and provide a new patch as soon as possible. Thanks once again for considering my input. Regards, s/KAM ----- Original Message ----- From: <bugzilla-daemon@xxxxxxxxxxxxxxxx> To: <KevinMyers@xxxxxxxxxxxxx> Sent: Wednesday, January 15, 2003 8:45 AM Subject: [Bug 103547] Changed - Initial Display Scale Too Small for High Aspect Ratio Images > http://bugzilla.gnome.org/show_bug.cgi?id=103547 > > > > > > ------- Additional Comments From sven@xxxxxxxx 2003-01-15 09:45 ------- > I haven't checked but I think the proposed solution has some > drawbacks. Think of an image of 2000x399 pixels. If we'd go for your > proposed change, the image would be displayed with a zoom ratio of 1:1 > while earlier versions of Gimp chose 1:2 or 1:3 to be able to display > the entire image. I don't want the behaviour for such common formats > to change. > > I'd like to propose two different solutions: > > (1) Limit the initial zoom ratio to 1:16. This would be consequent > since zooming in and out using the shortcuts does currently not > work if you are outside the 16:1 .. 1:16 range. > > (2) Add code that assures that the initial zoom ratio is choosen in > a way that assures that the smaller axis is not scaled down below > a minimal size of 1 pixel. > > I'd prefer solution (1) since it would reduce the time needed to open > a large image and create the initial display. Of course it means that > very large images (larger than 16 times the screen size) are not > displayed entirely when they are opened. As outlined in bug #62313, > this is broken anyway. So perhaps we should go for (1) but remove the > limitation for the zoom in / zoom out commands as I've already done in > the 1.3 tree.
Attachment:
scaleImage.sas
Description: application/sas
The SAS System 13:37 Wednesday, January 15, 2003 32
----------------------- Horizontal Screen Resolution=1280 Vertical Screen Resolution=1024 Previous Scale Factor=0.125 ------------------------
Horizontal Vertical
Horizontal Vertical Scale Scale Effective Scaled Scaled Horizontal Vertical Horizontal Vertical Horizontal Vertical
Image Image Factor Factor Scale Image Image Window Window Window Window Scrolling Scrolling
Size Size Numerator Denominator Factor Size Size Size Size Fraction Fraction Required Required
10 10 1 1 1.00000 10 10 10 10 1% 1% NO NO
10 100 1 1 1.00000 10 100 10 100 1% 10% NO NO
10 1000 1 2 0.50000 5 500 5 500 0% 49% NO NO
10 10000 1 10 0.10000 1 1000 1 768 0% 75% NO YES
10 100000 1 8 0.12500 1 12500 1 768 0% 75% NO YES
100 10 1 1 1.00000 100 10 100 10 8% 1% NO NO
100 100 1 1 1.00000 100 100 100 100 8% 10% NO NO
100 1000 1 2 0.50000 50 500 50 500 4% 49% NO NO
100 10000 1 14 0.07143 7 714 7 714 1% 70% NO NO
100 100000 1 8 0.12500 12 12500 12 768 1% 75% NO YES
1000 10 1 2 0.50000 500 5 500 5 39% 0% NO NO
1000 100 1 2 0.50000 500 50 500 50 39% 5% NO NO
1000 1000 1 2 0.50000 500 500 500 500 39% 49% NO NO
1000 10000 1 14 0.07143 71 714 71 714 6% 70% NO NO
1000 100000 1 8 0.12500 125 12500 125 768 10% 75% NO YES
10000 10 1 10 0.10000 1000 1 960 1 75% 0% YES NO
10000 100 1 11 0.09091 909 9 909 9 71% 1% NO NO
10000 1000 1 11 0.09091 909 90 909 90 71% 9% NO NO
10000 10000 1 14 0.07143 714 714 714 714 56% 70% NO NO
10000 100000 1 11 0.09091 909 9090 909 768 71% 75% NO YES
100000 10 1 8 0.12500 12500 1 960 1 75% 0% YES NO
100000 100 1 8 0.12500 12500 12 960 12 75% 1% YES NO
100000 1000 1 8 0.12500 12500 125 960 125 75% 12% YES NO
100000 10000 1 14 0.07143 7142 714 960 714 75% 70% YES NO
------------------------- Horizontal Screen Resolution=1280 Vertical Screen Resolution=1024 Previous Scale Factor=1 --------------------------
Horizontal Vertical
Horizontal Vertical Scale Scale Effective Scaled Scaled Horizontal Vertical Horizontal Vertical Horizontal Vertical
Image Image Factor Factor Scale Image Image Window Window Window Window Scrolling Scrolling
Size Size Numerator Denominator Factor Size Size Size Size Fraction Fraction Required Required
10 10 1 1 1.00000 10 10 10 10 1% 1% NO NO
10 100 1 1 1.00000 10 100 10 100 1% 10% NO NO
10 1000 1 2 0.50000 5 500 5 500 0% 49% NO NO
10 10000 1 10 0.10000 1 1000 1 768 0% 75% NO YES
10 100000 1 1 1.00000 10 100000 10 768 1% 75% NO YES
100 10 1 1 1.00000 100 10 100 10 8% 1% NO NO
100 100 1 1 1.00000 100 100 100 100 8% 10% NO NO
100 1000 1 2 0.50000 50 500 50 500 4% 49% NO NO
100 10000 1 14 0.07143 7 714 7 714 1% 70% NO NO
100 100000 1 1 1.00000 100 100000 100 768 8% 75% NO YES
1000 10 1 2 0.50000 500 5 500 5 39% 0% NO NO
1000 100 1 2 0.50000 500 50 500 50 39% 5% NO NO
1000 1000 1 2 0.50000 500 500 500 500 39% 49% NO NO
1000 10000 1 14 0.07143 71 714 71 714 6% 70% NO NO
1000 100000 1 2 0.50000 500 50000 500 768 39% 75% NO YES
10000 10 1 10 0.10000 1000 1 960 1 75% 0% YES NO
10000 100 1 11 0.09091 909 9 909 9 71% 1% NO NO
10000 1000 1 11 0.09091 909 90 909 90 71% 9% NO NO
10000 10000 1 14 0.07143 714 714 714 714 56% 70% NO NO
10000 100000 1 11 0.09091 909 9090 909 768 71% 75% NO YES
100000 10 1 1 1.00000 100000 10 960 10 75% 1% YES NO
100000 100 1 1 1.00000 100000 100 960 100 75% 10% YES NO
100000 1000 1 2 0.50000 50000 500 960 500 75% 49% YES NO
100000 10000 1 14 0.07143 7142 714 960 714 75% 70% YES NO
------------------------- Horizontal Screen Resolution=1280 Vertical Screen Resolution=1024 Previous Scale Factor=8 --------------------------
Horizontal Vertical
Horizontal Vertical Scale Scale Effective Scaled Scaled Horizontal Vertical Horizontal Vertical Horizontal Vertical
Image Image Factor Factor Scale Image Image Window Window Window Window Scrolling Scrolling
Size Size Numerator Denominator Factor Size Size Size Size Fraction Fraction Required Required
10 10 1 1 1.00000 10 10 10 10 1% 1% NO NO
10 100 1 1 1.00000 10 100 10 100 1% 10% NO NO
10 1000 1 2 0.50000 5 500 5 500 0% 49% NO NO
10 10000 1 10 0.10000 1 1000 1 768 0% 75% NO YES
10 100000 8 1 8.00000 80 800000 80 768 6% 75% NO YES
100 10 1 1 1.00000 100 10 100 10 8% 1% NO NO
100 100 1 1 1.00000 100 100 100 100 8% 10% NO NO
100 1000 1 2 0.50000 50 500 50 500 4% 49% NO NO
100 10000 1 14 0.07143 7 714 7 714 1% 70% NO NO
100 100000 8 1 8.00000 800 800000 800 768 63% 75% NO YES
1000 10 1 2 0.50000 500 5 500 5 39% 0% NO NO
1000 100 1 2 0.50000 500 50 500 50 39% 5% NO NO
1000 1000 1 2 0.50000 500 500 500 500 39% 49% NO NO
1000 10000 1 14 0.07143 71 714 71 714 6% 70% NO NO
1000 100000 1 2 0.50000 500 50000 500 768 39% 75% NO YES
10000 10 1 10 0.10000 1000 1 960 1 75% 0% YES NO
10000 100 1 11 0.09091 909 9 909 9 71% 1% NO NO
10000 1000 1 11 0.09091 909 90 909 90 71% 9% NO NO
10000 10000 1 14 0.07143 714 714 714 714 56% 70% NO NO
10000 100000 1 11 0.09091 909 9090 909 768 71% 75% NO YES
100000 10 8 1 8.00000 800000 80 960 80 75% 8% YES NO
100000 100 7 1 7.00000 700000 700 960 700 75% 68% YES NO
100000 1000 1 2 0.50000 50000 500 960 500 75% 49% YES NO
100000 10000 1 14 0.07143 7142 714 960 714 75% 70% YES NO
