Zooming Point

[Robert Schleif]

When using the mouse wheel to zoom an image, and when a cursor is within an image at the time the wheel rotation begins, is it feasible for that part of the image to remain viewable regardless of the amount of zoom? That is, could the zooming be centered at the original cursor position? When I zoom in, I generally want to see what happens in a specific part of the image. After zooming, I usually have to go back and find my area of interest. It would be nice if I didn't have to.

[Marpel]

Funny enough, not sure if this was intentional or not, but it almost does that now.

If you hold the cursor in the center and zoom or zoom with the buttons, the image zooms to the center. But if you place the cursor towards the edge or four corners, away from the center, when zooming starts, the image zoom point shifts a bit (not completely to the cursors position) towards where the cursor had been positioned. So it seems the program is already somehow recognizing the position of the cursor.

Marv

[jsachs]

When you zoom in with the mouse wheel, it tries to center to point you are zooming in on and then moves the cursor to the center of the displayed image so that further zooms keep the same point centered. If you are near an edge, it can't always center the part of the image under the cursor, so there can be some drift.

There are probably better ways to implement this -- will see what I can do when I get a chance.

[tomczak]

This may be obvious, and I also tend to do zooming with the mouse wheel, but there is a Magnifier Tool which may do what Robert wanted in the first post.

[jsachs]

I improved the way the mouse wheel scrolls in or out for the next release, so as to keep the cursor fixed on the same part of the image as you zoom in or out.l

[Marpel]

Just spent the last couple hours comparing different sharpening settings for an image. And to view (and scroll) and compare the same section(s) in each version, I found I was having to zoom each to the same zoom factor, then Alt + the arrow keys on both images (with the exact number of clicks) to get the view for each image on the same spot, then click each image thumbnail back and forth. I find the Compare tool doesn't have the ability to easily scroll around the images.

Having said all that, Maciej reminded me of the Magnifier tool which, I just found out, allows two images to be easily scrolled and compared by using Composite (just have one image as the base image and the other version in the Overlay box and leave blend as default) with Magnify in the side by side mode. Any position you click in one image is replicated in the other. And the zoom factor is variable.

So thanks for that.

Marv

[jsachs]

You could also just use your Composite technique with the Composite transformation set to side by side display and let the synchronized zooming and scrolling do the same as the magnifier.

I do plan to improve the scrolling in Compare -- it does have scroll bars now, but you can't easily drag the preview around.

[Marpel]

Jonathan,

Using Composite as you suggest is also possible but I find the Magnifying Tool better for two reasons - Scrolling the hand in Composite only works smoothly at 1:1, anything less, or more, causes the image to sort of stutter as it moves, making it slower than at 1:1 - And I like to see the entire image, to be able to quickly choose different locations to place the cursor (e.g. the image I was referring to is a long exposure of waterfalls, with a river in front and rocks and plants throughout) then visually compare the two versions at the different spots. In this case, I determined that a mask was required in some areas to decrease the sharpening effect in parts of the water while maintaining the full sharpening in the foliage.

Marv

[Robert Schleif]

The new zoom works great and is a real convenience. Thank you.

[jsachs]

For the next release, I also added scrolling to Compare by Alt-dragging on the preview area.