When working with various software more or less related to graphics editing - be it map makers, CAD, 3D modellers or such, I often need to redraw certain contents of some image I have as a bitmap.
It would be extremely helpful if I could place the bitmap in question as overlay on top of the drawing canvas, set its opacity to 50% and then just use the tools of the software I use to replicate the shapes I need. Unfortunately in many cases the software I use doesn't provide ability to put overlays (or use a simple single low-res .jpg as overlay) In this case an external program to display the "overlay" on top of the canvas would be helpful - just drag the image display window over the editor, set the scale right, and edit away! (providing clicking over the image sends the click to the editor, not to the image viewer!)
Example: the newspaper published an infographics with the map of a planned new city car route in my city. I'd like to add it to OpenStreetMap, but the provided map is sketchy at best, denoting a few streets and keeping general proportions but no finer details. I'd be able to overlay it and scale to match street layout, then just draw the route where it's shown on the plan. Unfortunately, OSM editor allows only tileset server for overlays - no simple local file bitmaps.
- Display image with partial opacity (either settable from the program/fixed or inherent - PNG alpha, I can add this to image myself)
- pan and scale image to place it precisely (non-essential)
- don't steal focus when the image is clicked, pass click to window below
- stay on top, even when the window below is focused.
Note these apply just to the image displayed. What happens to the UI/window/whatever of the viewer application when a different application is focused is irrelevant. I'm open for both free and commercial solutions, Windows preferred but Linux acceptable too.
Is there a program to provide such functionality?