I'm using CHtmlView (MFC wrapper class for IWebBrowser2) to show an SVG file, and wheel zoom is doing something crazy. If I hold down the Control key and spin the mouse Wheel UP, the image zooms IN at the mouse cursor, as expected. The problem is, spinning the mouse wheel DOWN does THE SAME THING. There appears to be no way to zoom OUT. I have tried every combination of control keys and none of them zoom out. If I open the SVG file in Internet Explorer, I get the exact same dumb behavior. I also tried using IWebBrowser2 directly (without CHtmlView) and again the behavior is the same.
I tried various SVG files, but they all exhibit the bug. If I open the same SVG file in Firefox, wheel zoom works as expected. So I conclude there's nothing special about the SVG file.
I tried using CHtmlView to open a PDF file, and again wheel zoom works fine in both directions. This leads to me believe that the problem is with whatever component Internet Explorer uses to display SVG files. What component is that? Is SVG support built-in to IE 10, or is it using a plugin?
I'm running Windows 7, Internet Explorer version 10.0.9200.16737. I tried using FEATURE_BROWSER_EMULATION to change the IE version to 10000 for my application but it made no difference. I didn't expect it to help, since Internet Explorer also exhibits the bug by itself, without my application.
I looked into the possibility of writing custom zoom code, but it looks dubious, because my requirement is not merely to zoom in/out, but to zoom in/out at the pointer position. Code such as ExecWeb(OLECMDID_OPTICAL_ZOOM, OLECMDEXECOPT_DODEFAULT, &vZoom, NULL); is unlikely to solve my problem, because there is no parameter for the current pointer position.
I searched on this problem for hours and astonishingly did not find any relevant information. I can't believe I'm the first to notice this behavior, UNLESS it's only happening to me because there's something unique about my OS configuration.
