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Using a bitmap created with ms paint

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B b_girl

Hey... I have yet another bitmap question. I used MS Paint to create a bitmap, and I recorded the red, green and blue intensities for each colour I used. In my program, I take these intensities and turn it into COLORREF, using RGB(r,g,b). Later on, after the user clicks on part of the bitmap, I determine where the click occurred and what the colour is at that point using GetPixel(..). The COLORREF value returned by GetPixel never matches the original COLORREF value. I have tried re-doing the colours (once again, in ms paint) but it still doesn't work. Are the values that ms paint uses for r g b the same throughout everything?
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Terry ONolley

wrote on last edited by

#3

Is your screen display running at 24-bit color? I think that if your monitor is set to a lower color depth then when your bitmap is BitBltted to the DC it gets dithered down to match your display settings.
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J Jason Henderson

Did you save the image as a 24 bit bitmap? IF yousaved it as 256 color bitmpa it may have messed some of them up.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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b_girl

wrote on last edited by

#4

I didn't see that it could be saved as different types. If I save as 24 bit bitmap as opposed to 256 colour bitmap, will end users of this have problems with the colours like I did? Or should that avoid other people having problems with it as well?
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B b_girl

I didn't see that it could be saved as different types. If I save as 24 bit bitmap as opposed to 256 colour bitmap, will end users of this have problems with the colours like I did? Or should that avoid other people having problems with it as well?
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Jason Henderson

wrote on last edited by

#5

See Terry's post. I would use windows standard colors if possible. You 256 to choose from.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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J Jason Henderson

See Terry's post. I would use windows standard colors if possible. You 256 to choose from.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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b_girl

wrote on last edited by

#6

Yeah, I read his post. It was set at 16 before, but I've switched it to 24-bit. I have the colours on my bitmap all sorted out now, it all works just fine. But I'm scared that there will be problems with end users. Are the windows standard colours the 24-bit? Or is it 32-bit or 256? By using 24 bit, and having everything saved in 24 bit, there shouldn't be any problems with people using it who are using more colour right? (just the people using less colour would run into a problem I suppose)
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B b_girl

Yeah, I read his post. It was set at 16 before, but I've switched it to 24-bit. I have the colours on my bitmap all sorted out now, it all works just fine. But I'm scared that there will be problems with end users. Are the windows standard colours the 24-bit? Or is it 32-bit or 256? By using 24 bit, and having everything saved in 24 bit, there shouldn't be any problems with people using it who are using more colour right? (just the people using less colour would run into a problem I suppose)
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Jason Henderson

wrote on last edited by

#7

I would guess that most users would have 16 bit color or higher selected. If you do use a 24bit color bitmap and use a color outside of the windows palete, then that color will not display correctly and your GetPixel will fail. If you confine you colors to the defaut windows palete, you shouldn't have any problem.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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J Jason Henderson

I would guess that most users would have 16 bit color or higher selected. If you do use a 24bit color bitmap and use a color outside of the windows palete, then that color will not display correctly and your GetPixel will fail. If you confine you colors to the defaut windows palete, you shouldn't have any problem.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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b_girl

wrote on last edited by

#8

what is the default windows palete?
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B b_girl

what is the default windows palete?
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Jason Henderson

wrote on last edited by

#9

Its a list of 256 different colors. You may be able to find them on the web. The colors I setup in that template bitmap I sent you should all be in that palete. Windows does some funky things to the colors in 256 color mode. I really wouldn't worry about it too much though.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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J Jason Henderson

Its a list of 256 different colors. You may be able to find them on the web. The colors I setup in that template bitmap I sent you should all be in that palete. Windows does some funky things to the colors in 256 color mode. I really wouldn't worry about it too much though.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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b_girl

wrote on last edited by

#10

I could only get 3 of the elements to actually work properly from that template bitmap you sent me. I tried redoing it, and it works now (I'm reading in r,g,b instead of COLORREF) but it won't work if the display is set at 256 colours. I can't seem to find a list of the 256 colours online or anything, but if I have my settings set at 256 and I redo the template bitmap, it should only allow me to use the 256 colours right? I have grown to dislike different colour settings.
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B b_girl

I could only get 3 of the elements to actually work properly from that template bitmap you sent me. I tried redoing it, and it works now (I'm reading in r,g,b instead of COLORREF) but it won't work if the display is set at 256 colours. I can't seem to find a list of the 256 colours online or anything, but if I have my settings set at 256 and I redo the template bitmap, it should only allow me to use the 256 colours right? I have grown to dislike different colour settings.
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Jason Henderson

wrote on last edited by

#11

In 256 color mode, Windows will only have 256 colors available fo rthe screen display at one time. If you use too many colors, it will convert them to the closest matching color in the current palete. The screen would look like a rainbow of sorts. Since the template bitmap is selected into a device context that is compatible with the screen, then it will be converted to the same color depth as the screen. There really is no way to control it, but you can make your app use the same color palete in all of its bitmaps and windows, etc. If you use this palette http://www.soc.hawaii.edu/com337/presentations/presentation_04/sld017.htm[^] you should be ok.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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B 1 Reply Last reply

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J Jason Henderson

In 256 color mode, Windows will only have 256 colors available fo rthe screen display at one time. If you use too many colors, it will convert them to the closest matching color in the current palete. The screen would look like a rainbow of sorts. Since the template bitmap is selected into a device context that is compatible with the screen, then it will be converted to the same color depth as the screen. There really is no way to control it, but you can make your app use the same color palete in all of its bitmaps and windows, etc. If you use this palette http://www.soc.hawaii.edu/com337/presentations/presentation_04/sld017.htm[^] you should be ok.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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b_girl

wrote on last edited by

#12

Is there anywhere to find the r,g,b values of the colours in that palette? Or do I have to just look at that and figure out the values by just trying to match it up as best as I can? I only need 92 distinct colours, and I tried setting my display to 256 thinking that only those 256 colours would be available to me, but it's still adjusting the colour values, so I have no idea what to use as colours anymore.
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B b_girl

Is there anywhere to find the r,g,b values of the colours in that palette? Or do I have to just look at that and figure out the values by just trying to match it up as best as I can? I only need 92 distinct colours, and I tried setting my display to 256 thinking that only those 256 colours would be available to me, but it's still adjusting the colour values, so I have no idea what to use as colours anymore.
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Jason Henderson

wrote on last edited by

#13

Download a shareware paint program or invest in Paint Shop Pro (www.jasc.com). MS Paint just doesn't cut it. Like I said before, I wouldn't worry about making it compatible with 256 color modes. I don't know anybody that still uses that mode. If they do, they could easily move up to 16 bit.

"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt." - Abraham Lincoln

Jason Henderson
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