Re: [Flightgear-devel] OT: Gimp and small textures
On Wed 2. April 2003 19:07, you wrote: But are you starting with an image of 1024x1024 or higher? If you try to edit at the final resolution, you really can't avoid seeing aliasing artifacts. Everything has to be done in a giant buffer and then downsampled as the very last step. I am starting at 512x512 so downsample 4x. I draw lines with antialiasing on. I have one more question. Is it posible and how to specify color in postscript by RGB components? Sure: 0 0 1 setrgbcolor ...will set the drawing color to pure blue. The numbers are floating point in the range 0-1. Postscript color space handling gets obtusely complicated, but this one does what most programmers expect and is especially useful for situations like this where the only display device is a bitmapped RGB image. And yes, the arguments come before the function. Postscript is a postfix stack language like forth. :) Andy Thanks, Madr -- Martin Dressler e-mail: [EMAIL PROTECTED] http://www.musicabona.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] OT: Gimp and small textures
I have one more question. Is it posible and how to specify color in postscript by RGB components? Have you looked at the language specification? http://partners.adobe.com/asn/developer/pdfs/tn/PLRM.pdf In case it's not in the core language, it should be trivial to define your own command. -Gerhard -- | voice: +43 (0)676 6253725 *** web: http://www.cosy.sbg.ac.at/~gwesp/ | | Passts auf, seid's vuasichdig, und lossds eich nix gfoin! | -- Dr. Kurt Ostbahn ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] OT: Gimp and small textures
Martin Dressler wrote: So it mean that gimp use bad antialiasing or render lines in some bad way. Because Gimp scale with the same quality as ImageMagic. But are you starting with an image of 1024x1024 or higher? If you try to edit at the final resolution, you really can't avoid seeing aliasing artifacts. Everything has to be done in a giant buffer and then downsampled as the very last step. I have one more question. Is it posible and how to specify color in postscript by RGB components? Sure: 0 0 1 setrgbcolor ...will set the drawing color to pure blue. The numbers are floating point in the range 0-1. Postscript color space handling gets obtusely complicated, but this one does what most programmers expect and is especially useful for situations like this where the only display device is a bitmapped RGB image. And yes, the arguments come before the function. Postscript is a postfix stack language like forth. :) Andy -- Andrew J. RossBeyond the OrdinaryPlausibility Productions Sole Proprietor Beneath the Infinite Hillsboro, OR Experience... the Plausible? ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] OT: Gimp and small textures
On Mon 31. March 2003 19:53, you wrote: Martin Dressler wrote: I made some investigations in last days and find why my textures look so bad when scaled down to 128x128 textures compared to textures generated by perl scripts (writen by Andy?) Uh, once upon a time, yeah. They're terrible hacks; not exactly my best work. :) But works good, I only don't like, that it is perl :o) The problem isn't in scaling, because these scripts scale down too, but the diference is in how gimp render lines and ghostscript render lines. No, it's the scaling. Ghostscript doesn't do antialiasing at all, it just colors whole pixels. The scripts use gs to rasterize the image at 4x (or even 16x, to get the whole 8 bit gray range) resolution and then downsample to the target resolution using ImageMagick's mogrify program. So it mean that gimp use bad antialiasing or render lines in some bad way. Because Gimp scale with the same quality as ImageMagic. Is it posibble to change these scripts to produce dials with fully transparent background, or give them some texture to render on it. The original scripts hack in alpha by using a chroma key. If you draw anything in pure blue (I think), it'll come out transparent. This actually exploits Ghostscript's inability to do sub-pixel rendering. I think the alpha stuff was actually done with a tiny C program, but I forget. :) A tiny perl program. So if I delete background, It will render in white on pure blue and after scale down I will get transparent layer with white lines only. It is exactly what i wanted. I have one more question. Is it posible and how to specify color in postscript by RGB components? Thank, Madr -- Martin Dressler e-mail: [EMAIL PROTECTED] http://www.musicabona.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] OT: Gimp and small textures
Hi, I made some investigations in last days and find why my textures look so bad when scaled down to 128x128 textures compared to textures generated by perl scripts (writen by Andy?) The problem isn't in scaling, because these scripts scale down too, but the diference is in how gimp render lines and ghostscript render lines. The text looks same when rendered with freetype library. I don't want to throw out the posibility to draw on texture. Is it posibble to change these scripts to produce dials with fully transparent background, or give them some texture to render on it. Thanks, Madr -- Martin Dressler e-mail: [EMAIL PROTECTED] http://www.musicabona.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] OT: Gimp and small textures
Martin Dressler wrote: I made some investigations in last days and find why my textures look so bad when scaled down to 128x128 textures compared to textures generated by perl scripts (writen by Andy?) Uh, once upon a time, yeah. They're terrible hacks; not exactly my best work. :) The problem isn't in scaling, because these scripts scale down too, but the diference is in how gimp render lines and ghostscript render lines. No, it's the scaling. Ghostscript doesn't do antialiasing at all, it just colors whole pixels. The scripts use gs to rasterize the image at 4x (or even 16x, to get the whole 8 bit gray range) resolution and then downsample to the target resolution using ImageMagick's mogrify program. Is it posibble to change these scripts to produce dials with fully transparent background, or give them some texture to render on it. The original scripts hack in alpha by using a chroma key. If you draw anything in pure blue (I think), it'll come out transparent. This actually exploits Ghostscript's inability to do sub-pixel rendering. I think the alpha stuff was actually done with a tiny C program, but I forget. :) Alternatively, you can take the gray scale texture and use it as an alpha channel underneath pure white (or black). That will get you the effect you want. If gimp can't do this, you can write a really trivial C program to turn the grayscale image into a raw RGBA file, thence to a .png or whatnot using ImageMagick. Andy -- Andrew J. RossBeyond the OrdinaryPlausibility Productions Sole Proprietor Beneath the Infinite Hillsboro, OR Experience... the Plausible? ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
