Changing a colors brightness?

[shadowrecon]

Anyone have any ideas on settings a color to a different brightness ? I've wrote a function to change to opacity but it can only make the color darker. I'd like a function that does the opposite.

[scar]

function opacity(color: integer; percent: extended): integer;

Var

R,g,b: integer;

Begin

Percent := percent / 100;

Colortorgb(color,r,g,b);

Result := Rgbtocolor(

Round((1 - percent)*r),

Round((1 - percent)*g),

Round((1 - percent)*b));

End;

[/scar]

[FHannes]

Why not convert it to HSL, change the luminosity and convert it back?

[shadowrecon]

The reason is I'm working on this plugin and I'm going to be changing every pixel in the bmp and I know how to convert a color to rgb and back but have no clue how to convert it to HSL and back. That would be a lot easier tho.

[FHannes]

http://www.easyrgb.com/index.php?X=MATH&H=18#text18

 

The next revisions of the samples repository will contain a library sample which demonstrates drawing on bitmaps in scar from libraries, and exporting bitmaps from scar to the library and the other way around. but I'll need to upload a new beta before I can implement all of that properly.

[shadowrecon]

http://www.easyrgb.com/index.php?X=MATH&H=18#text18

 

The next revisions of the samples repository will contain a library sample which demonstrates drawing on bitmaps in scar from libraries, and exporting bitmaps from scar to the library and the other way around. but I'll need to upload a new beta before I can implement all of that properly.

Thanks for the link! Right now for bitmaps I'm just using the DC, and creating a canvas and setting the handle to the dc which works really good so far. My lib takes 5ms and scar takes 9 seconds to do the same procedure on a 50 x 50 bitmap

[FHannes]

The pascalscript engine SCAR uses is very slow compared to native code. Usually it's not such a big problem, but when you need to write high-performance algorithms, it is.

[LordJashin]

The pascalscript engine SCAR uses is very slow compared to native code. Usually it's not such a big problem, but when you need to write high-performance algorithms, it is.

So if certain things run slow make sure they aren't in a scar library?

[shadowrecon]

Yeah that's the whole reason I had to write a lib. Because the time it took to convert and replace 2500 pixels. In your example of bitmaps could you possibly make a scanline version? Because I tried using scanline but couldn't get it to work right and from what or read it is a heck of alot faster then canvas.pixels[]

[FHannes]

So if certain things run slow make sure they aren't in a scar library?

 

Make sure they are... Though, you'll only ever need this for very high performance algorithms that need to change or check tons of data or make huge calculations.

 

---------- Post added at 11:14 PM ---------- Previous post was at 11:10 PM ----------

 

Yeah that's the whole reason I had to write a lib. Because the time it took to convert and replace 2500 pixels. In your example of bitmaps could you possibly make a scanline version? Because I tried using scanline but couldn't get it to work right and from what or read it is a heck of alot faster then canvas.pixels[]

 

Take a look at this topic I wrote when I was 16 It should give you a good idea on how to use scanlines: http://forums.freddy1990.com/index.php/topic,8.0.html

It uses a TBitmap, but the upcoming sample will show you how to get a bitmap from SCAR to a TBitmap in a library.

[LordJashin]

Make sure they are... Though, you'll only ever need this for very high performance algorithms that need to change or check tons of data or make huge calculations.

 

---------- Post added at 11:14 PM ---------- Previous post was at 11:10 PM ----------

 

 

Take a look at this topic I wrote when I was 16 It should give you a good idea on how to use scanlines: http://forums.freddy1990.com/index.php/topic,8.0.html

It uses a TBitmap, but the upcoming sample will show you how to get a bitmap from SCAR to a TBitmap in a library.

There are tutorials around on bitmaps, canvases, etc.

 

So Freddy how is what he's doing a high performance algorithm? Explain I'm brain dead atm, and also

 

Offtopic: Does anyone know any good websites to learn algebra, or just math in general. I like to learn thoroughly, I don't like just skimming a topic then using it later and not understanding it fully. Help...

 

Thanks for the link Freddy looks indepth - http://forums.freddy1990.com/index.php/topic,8.0.html

Edited April 4, 2012 by LordJashin

[FHannes]

The algorithm he wants to write is extremely CPU intensive because of the "heavy" calculations required to convert the RGB values to HSL and back. Normally this wouldn't be a problem, but he has to do it for every pixel on a bitmap, if you have a small bitmap, let's say 50*50, that's 2500 times you have to perform all of those calculations. That would still execute at acceptable speeds in SCAR, but if you examine a more realistic example, lets say a 1000*500 bitmap, that's 500000 pixels.

 

EDIt: The new sample is up, make sure you have the latest beta copy.

Edited April 4, 2012 by Freddy

[shadowrecon]

Thanks freddy all of this information has been really helpful!