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Re: [ft] Regression in font clarity with Adobe engine
From: |
Dave Arnold |
Subject: |
Re: [ft] Regression in font clarity with Adobe engine |
Date: |
Tue, 14 Jan 2014 10:17:51 -0800 |
User-agent: |
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 |
Hi Mike,
I don't know what setting "X.org gamma" does, but it sounds like it might be
the wrong place to look. I'm not talking about changing a system setting for your
monitor. Your monitor should most commonly be in a non-linear space, like sRGB. That's
necessary for displaying most images, photos, videos, etc. The gamma I am talking about
is used used for compositing anti-aliased text into an image. Anti-aliasing requires the
blending operation to be done in a linear color space. When compositing into a non-linear
space, the steps are:
1) convert foreground (text color) and background pixels to a linear color
space
2) blend the two colors according to the anti-alias density (alpha) value
3) convert the result back to the original non-linear space
This calculation is performed only in the code that composites anti-aliased
text. The calculation needn't be precise, so a simple table lookup of a power
function with an exponent (gamma) of about 1.8 can be used.
Thanks.
-Dave
On 1/14/2014 8:33 AM, Michael Cronenworth wrote:
Yes, your assumption is correct. X.org defaults to 1.0 gamma and any screenshot
results in 1.0 gamma. Setting my X.org gamma to 1.8 makes my screen look like
the surface of the sun. Not a good option.