Relative zoom calculation: a drawback

[Bhikkhu Pesala]

Holy cow Bhikkhu! What the heck?! Who cares about all the math?

All the geometric, logarithmic, linear, isometric, barometric, bombastic or anything else calculations are not needed.

Please read the forum survival guide again.

Treat others as you want to be treated. Flaming, insults or defamation will not be tolerated. Use a friendly conversation tone.

When resampling is on, zooming in and out is slow, especially if zooming in small steps from say, 500% to 1000%. With the current geometric progression it is faster and takes few keystrokes.

Irfan clearly thought that there were disadvantages to using a single arithmetic step of 10% — that is why he introduced the new method. There is also a problem when using a large step and zooming out. 100%, 50% then nothing because it won't zoom to 0%.

Hopefully, the next version will be improved, but we may have to put up with the current unsatisfactory state of affairs for another six months or more. Entering a precise zoom value by clicking on the status line would be useful. DrawPlus has it all:

1. A zoom slider that follows a geometric progression (shortcut keys do too).
2. Plus and Minus buttons for zooming in and out.
3. A popup list from which one can select a predefined value.
4. A zoom field, into which one can type a precise value.

[j7n]

A predefined list of zoom values is indeed the best solution, as long as one can zoom to 25% and 50%. I see DrawPlus has those.

we may have to put up with the current unsatisfactory state of affairs for another six months or more

Not really. We can use v4.00.

[Bhikkhu Pesala]

Not really. We can use v4.00.

But then we cannot use IrfanPaint, which is even more unsatisfactory.

[ChuckE]

Not really. We can use v4.00.

But then we cannot use IrfanPaint, which is even more unsatisfactory.

Again, not really, since IrfanPaint only requires a call from IrfanView, which was available (since the middle of July '07) as a modified v4.0 from MItaly.

The modified i_view32.exe, the main IrfanView executable, which has the <F12> call for IrfanPaint, does not care which version of the IrfanPaint is installed. Just that the plug-in is in the correct place.

So, you can get the modified v4.0 from MItaly's website, and use the latest version of his really nice plug-in, IrfanPaint.

[ChuckE]

Please read the forum survival guide again.
"Quote:
Treat others as you want to be treated. Flaming, insults or defamation will not be tolerated. Use a friendly conversation tone."

What are you talking about? where is the flaming, insult, or defamation? If you were here in my presence I would have said exactly what I wrote, and you would not have been offended in any way. I'm sorry that the intended lightened tone does not convey as well in a typed reply. There was no denigration intended in anything I wrote. Why are you so thin-skinned to feel so? This brings to mind where some people get upset with cartoons of Muhammad.

Golly, lighten up. Or does that bother you too?
If so, then please put your hands on your computer and feel the warmth of my sincerity.
Note: All of the above was stated in a friendly conversational tone.

[MItaly]

Again, not really, since IrfanPaint only requires a call from IrfanView, which was available (since the middle of July '07) as a modified v4.0 from MItaly.

The modified i_view32.exe, the main IrfanView executable, which has the <F12> call for IrfanPaint, does not care which version of the IrfanPaint is installed. Just that the plug-in is in the correct place.

So, you can get the modified v4.0 from MItaly's website, and use the latest version of his really nice plug-in, IrfanPaint.

Actually it's a bit more complicated. The call to the IrfanPaint exported function (ShowIrfanPaintTB) is just the smallest change done to IrfanView in order to make IrfanPaint work. IrfanPaint also requires IV to reply to some new window messages (actually 8, but they may grow in future), without which it's completely lost. It's true that from the last pre-IV4.10 beta we didn't add any other message, but you cannot rely on this assumption (in fact I was going to propose to Irfan to add some kind of version check between IV and IP to prevent mixed-versions problems). Moreover, the pre-IV4.10 betas use a beta exe, that has bugs and unfinished features: who got involved in the beta testing may remember this problem, and what Irfan said about the beta exes.

When resampling is on, zooming in and out is slow, especially if zooming in small steps from say, 500% to 1000%.

An improvement for this could be to make the zoom work a little like the Google Maps zoom: the image is first zoomed roughly (without resampling), then, if you don't continue to zoom, it's rendered better (with resampling).

[Sam_Zen]

2 ChuckE
Don't make the same 'edgy' mistake by comparing this with cartoon idiocy.

By the way, I take the zooming business for granted, because I prefer a functioning IrfanPaint with 4.10.

2 MItaly
The Google Maps zoom indeed is quite an elegant procedure.

[beerslayer]

Prefer original &quot;absolute&quot; zoom method...

I agree with much of what's been said in this thread. I greatly prefer the old ("absolute"?) zoom method to the new "relative" zoom.

All of this talk about calculating percentages and whatever seem far too complicated for my tastes. I originally started using IrfanView (way back in the 2.x days) because it struck a nice balance between functionality and friendliness. If I have to calculate fractional zoom percentages just to get to 100% (or 200%, or 500%), it's not worth my trouble any more.

While I understand that some users may prefer the new method, this should really be an option to be set in the program's preferences. It seems to me that it ought to be easy - the code to do both forms of zoom is already written! A simple check box under Options would suffice. I would really like to have the option to go back to the original zoom method in the next version.

[Neuron]

Zoom

I just wanted to add that I am also disappointed in the new zoom feature. I have reverted back to IrfanView 4.00 since the zoom feature is more important to me than any of the improvements in 4.10.

Hopefully, there will be a choice between the two in the next release, although I do not see any reason for a "relative" zoom. Zoom was not broke, no need to fix it...

[Bhikkhu Pesala]

The reason for the relative zoom feature is that it takes many fewer key strokes, and gives you much finer control when zooming out. I can tell you that the relative zoom in DrawPlus is excellent. You can get a feel for how well it works by zooming in PDF-XChange. That zooms from 1% to 6400% in 23 steps. Try that in IrfanView 4.00 and see how many steps it takes. 10% to 1000% is the maximum range IIRC, but it takes many more key presses.

IrfanView's implementation for 4.10 is broken in several respects, and definitely needs fixing. We don't need to take a backward step to the old zooming method with all of its limitations and disadvantages. Set your zoom step to 50% and you can no longer zoom down below 50%, etc. Set it to 1% and takes ages to zoom to 999%

[beerslayer]

I, personally, didn't see what was "broken" in the old zoom method. One of the things I loved about it was that I could set the zoom percentage to, say, 25%, and no matter what zoom factor an image used when it was fit to the screen, with a couple of keystrokes I could get it to exactly 100% (or 200%, or 50%). This is no longer an option with v4.10. I cannot even *make* the image display at exactly 100% without either getting very lucky or changing my display preferences!

Adding geometric stepping and the like doesn't do anything I need. I cannot imagine ever needing to view a .jpg or other lossy image at 6400%. They look bad enough at 400%. If I need that much precision, I'll use Photoshop or The Gimp.

For my needs, the old way wasn't a limitation or a disadvantage, and didn't need any fixing - it was simply convenient the way it was. That convenience is now gone. I am disappointed, and also dearly hoping it returns in v4.2 (or whatever the next release is).

Just one simple checkbox to choose "old vs. new" zoom functionality - that should make everyone happy. I don't see it as a step "backwards", merely providing "backwards compatibility" for those of us who saw no need to change it in the first place.

[Bhikkhu Pesala]

I, personally, didn't see what was "broken" in the old zoom method.

Nobody said it was. It is broken in 4.10 is what I said.

One of the things I loved about it was that I could set the zoom percentage to, say, 25%, and no matter what zoom factor an image used when it was fit to the screen, with a couple of keystrokes I could get it to exactly 100% (or 200%, or 50%). This is no longer an option with v4.10. I cannot even *make* the image display at exactly 100% without either getting very lucky or changing my display preferences!

Why anyone needs to zoom to exactly 200% is beyond me. Who cares if it is 200% or 195%? If you turn off the status line you will soon forget about it.

Zooming to 100% is simple — just press Control H.

I also hope this will be fixed — there is a serious bug if you set the zoom step to 100% — but geometric zooming itself is not a problem at all. Going back to the old way would be a regression as it has serious limitations when zooming out to view large images. Sure, you could change the step to 1%, but then you had to keep changing the step whenever you viewed average sized images, and change it again to a big step when viewing icons.

[Laurent]

Why anyone needs to zoom to exactly 200% is beyond me. Who cares if it is 200% or 195%? If you turn off the status line you will soon forget about it.

Zooming to 100% is simple — just press Control H.

Anyone loves round numbers: easy to remember, to calculate with. I hope the next version will restore the old way. When zooming in and out we coma back to the same level.

Laurent

[j7n]

Raster graphics cannot be zoomed to an arbitrary level. In a good graphics viewer one must be able to zoom to exactly 50% and 25%. At exactly 1:2 or 1:4 the picture is still perfectly viewable without using complex resampling.

Ctrl-H is not a solution because you can't easily find this button combination without looking at the kbd.

I recall that the consensus was that we need a predetermined list of zoom steps: 10, 20, 25, 50, 75, 100, 150, 200, 300, 500, 1000.

[Bhikkhu Pesala]

Raster graphics cannot be zoomed to an arbitrary level. In a good graphics viewer one must be able to zoom to exactly 50% and 25%. At exactly 1:2 or 1:4 the picture is still perfectly viewable without using complex resampling.

Sorry to disappoint you, but raster graphics are still messed up at 25% or 50% if resampling is off, just as they are at arbitrary percentages. Monitors cannot display half a pixel any better than they can display 0.47 of a pixel. If you turned off the status line, you would not be able to tell which was a rounded number and which was not. One of the attached images is at 25% — the other is at some arbitrary percentage close to 25%

Ctrl-H is not a solution because you can't easily find this button combination without looking at the kbd.

Press F a couple of times if Control H is too long a stretch.

I recall that the consensus was that we need a predetermined list of zoom steps: 10, 20, 25, 50, 75, 100, 150, 200, 300, 500, 1000.

Yes, something like that would be fine, but it needs to go down to 5% and up to a bit more than 1000. Currently it goes up to nearly 4000% — 2000% (20x) would be more than enough.

When zooming in and out we come back to the same level.

Yes. That is important too.