PureBasic Forums - English

Yes, Rule 1 of forums..search around first. Apologies.

That looks very helpful but I'm trying to avoid using API calls. I don't really understand them anyway.

I want to convert a colour bitmap to a grayscale image. There's a Luminance formula for converting 24 bit to 8 bit (R * 0.3 + G * 0.5 + B * 0.2).

Easy enough to extract with POINT. Do the maths and I've then got a grid array of 8 bit entries. So, CreateImage an 8 bit depth image and plot the ...

Thanks for that. A bit complex for this noob - useful for me to try to work through it though.

Can I rephrase the question?

Is it realistic for me to work on a bitmap in memory without making any operating system calls? You say that the native PB commands are pretty quick.

The app is fairly ...

Still pretty new to PB.

I want to do some RGB or grayscale image Pixel data (image manipulation) work. I'd like these ops to work fast. This is probably best done by working directly on memory - and if necessary, using some simple assembly language routines (I did this for 8-bit MPU's many years ...

That doesn't really get me any further.

Are you saying that that the characters of a filename are NOT contained within a file? It's not an unreasonable suggestion - other operating systems do it. I seem to remember name data in MS-DOS files.

If it's not, where is it? Going back to my USB stick ...

Sorry to keep going on about .bmp files.

I want to read/analyse the header of a .bmp file on disk and do some stuff based on the analysis result.

I found this link helpful:

http://www.fortunecity.com/skyscraper/windows/364/bmpffrmt.html


But where's the filename? It must be embedded in the file ...

I'm still very much a PB beginner but getting a bit better with practice.

I want to simplify the 24 bit RGB data in a colour bitmap into a 'custom' 8-bit format (imagine it's a grayscale, although that's not exactly what I'll be doing). Assume the original image is a .jpg. I then want to do a bit ...

Thanks.

Exactly what I was trying unsuccessfully to do.

Thanks. I knocked together the code from a couple of examples - I guess I'll see the error next time.

Please can you advise on the second problem: once I've been through the file tree and double clicked on the file that I want, how do I get the filename$?

A real PB beginner here - been going about 2 weeks.

I want to show a directory (and contents) and get the user to select a (image) file which then gets loaded and worked on. Hard, huh?

What's wrong with this code:

If OpenWindow(0, 0, 0, 230, 220, "File example...", #PB_Window_SystemMenu | #PB ...