There are problems with how 24-bit bitmaps display in OI, at least in version 3.61. Could somebody (some developer or Revelation) with a current version (I'm still on 3.61) please tell me if the problems still exist. If it does, a reply from Revelation would be much appreciated.

Several developers have reported these problems over the times, among them Greg James, Tamos Santos, Colin Rule and myself. I don't think any of us have seen all symptoms before, however. It's only now a clearer picture appears.

The problems show at runtime. At design time bitmaps display OK. I hope that means the problems are easy to correct.

There are two different symptoms:

(1) OI displays the image dithered, with a sub-optimal quality at that.

(2) The image is slightly distorted - not all pixel rows and columns display correctly:

- the middle pixel row is displayed twice

- the bottom pixel row of the image is not displayed

- the middle pixel column is displayed twice

- the rightmost pixel column of the image is not displayed.

A possible workaround is to convert images to indexed colour (palettized, 256 colours). This is not a general solution, however. It may work when the images are designed for the application, but not when the application programmatically displays the users' own images, which often will be 24-bit.

I've prepared a couple of images well suited to testing. The symptoms might be easiest to spot with a "Clip" bitmap control setting. This file contains a 24-bit BMP image. This file contains the same image in 256 colours with the standard Windows 256 colour palette. At design time the 24-bit image is slightly better than the palettized one (assuming one's screen is set up with more than 256 colours). At runtime, with my OI 3.61, the 24-bit image degrades according to my description above. The result is like this image.

- Oystein -

[email protected]

Sorry about the URLs for the image files. Here are the correct ones:

I've prepared a couple of images well suited to testing. The symptoms might be easiest to spot with a "Clip" bitmap control setting. This file contains a 24-bit BMP image. This file contains the same image in 256 colours with the standard Windows 256 colour palette. At design time the 24-bit image is slightly better than the palettized one (assuming one's screen is set up with more than 256 colours). At runtime, with my OI 3.61, the 24-bit image degrades according to my description above. The result is like this image.

- Oystein -

[email protected]

Oystein-

I cannot view your images, but I believe that the problem was related to the imgman11.dll version.

I also believe that this was fixed in 3.7.2. From the 3.7.2 Readme:

Presentation Server

· Added support for an "orientaion" parameter for TILE event. (SYSREPOSEVENTEXES/SYSPROG*TILE.WINDOW.OIWIN*)

· Improved rendering of high color images. (OINSIGHT.EXE – 3.7.2)

Hope this helps-

Mike Ruane

I helped Revelation fix the bug they had in displaying images and can assure you that the images display beautifully in 3.7.2.

As for the offsetting of pixels half-way through the image, that problem *may* still be occurring only with certain color depths. I don't recall… it was months back.

Vince Poirier

Thanks, Mike and Vince.

Since Mike and Vince aren't 100% sure the pixel offset problem was solved completely, I'd still be interested in observations from others.

I cannot view your images

Mike - they are BMPs, so you cannot view them in your browser. I didn't convert to JPG or GIF because that would have changed the images. But are you saying you couldn't even download them? When you clicked them (the correct version) - weren't you offered to download them to your computer? I'd like to know. It might be some trivial thing with our web server.

- Oystein -

View this thread on the Works forum...