Mouse wheel smooth zoom in image viewer

Now the zoom step is too big, not only often stuck, but also the parts I want to see often miss. If the steps can be smaller and smoother, for example, each zoom only increases or decreases by 10%, the experience will be better.

How can I do this?

The mousewheel zoom steps can't be changed at the moment, but you can make buttons or hotkeys which zoom by a specified percentage, or directly to a specified percentage. See near the bottom of here for the Show VIEWERCMD=zoom,... command.

Leo, you are great!

Well done, thank you very much!

There seems to be a issue, I set Show VIEWERCMD=zoom, +/-10%. The first click to zoom in or out, the ratio is 50% or 25%, I did not find out what the law is, each time it is different, but then zoom in or out is 10%.

What's happening here?

If you put a space after the , then the +/-10% after it is going to be interpreted as a completely separate argument. Remove the space.

Sorry, the space is just that I was not careful when typing, not in DOpus.

DOpus execute other internal instructions on the first click, zooming in or out by 50% or 25%. After the second click, DOpus started to execute Show VIEWERCMD=zoom,+/-10%.

I guess DOpus can't determine the zoom ratio of the image for the first time. So it performs the usual practice, not the instructions I wrote. The image display ratio I set is fit to page, so the initial ratio of the image is different.

DOpus shows the absolute scale of the image, and I want to be the relative scale of the image. That is, no matter what the actual scaling is, I want to enlarge or reduce it by 10% based on this ratio.

Now, when displaying a large image, DOpus first executes the command to display the 100% image. After I click the zoom button, the cursor jumps to the original scale button, which is very strange.

If you go from Fit mode to zooming in/out in increments, it may not work as expected. I forget exactly how it works, but you might want to reset to 100% zoom first. The button could check if it's in fit mode and do that if it is.

I think the ideal way should be that regardless of the current image scaling, DOpus should use it as a reference point, assuming that the current zoom ratio is 100%, then click the button once to change a 10%, zoom in or out.

With fit/grow, that can result in never being able to get to exactly 100%, 200%, etc. which I know I find very annoying in Photoshop when trying to check pixel-level details or how things will look at standard DPI vs 200% scaling. (Lots of complaints about that on the Adobe forums.)

Maybe if it finds the next integer multiple of the offset. (Although that may be what it does already. I'd have to check.)

Browse the image with the image viewer, zoom in or out, without having to precisely control the zoom ratio of the image, just look at it, see the details as much as possible, 100% or 200% is not important at all. I just want to browse the picture smoothly and will handle it in Photoshop if needed.