On 2016-06-08 16:23, Anton Aylward wrote:
On 06/08/2016 08:50 AM, Carlos E. R. wrote:
When I capture a computer display with png
If you mean use a screen-scraper tool like KSnapshot then no wonder you get poor quality!
no no. A screen capture is by definition "maximum quality" always. It has a defined number of pixels, it is a memory image. There is no possible error. However, rendering it as a jpeg is always lossy, by definition. Some quality is lost, and you decide how much, in a compromise between quality and size.
and then convert to jpg with gimp (watching the quality-size balance)
OUCH again! Gimp is not the best tool to do a png -> gif or jpeg conversion
No, gimp is the perfect tool to convert to jpeg (I didn't say gif). Why? Because you can move the quality slider from 1 to 100 and watch the result dynamically, instantly, and decide how much quality you want to sacrifice. No other tool allows this. Because of this human decision procedure, the result is slow. But perfect.
Try 'convert' from the ImageMagick package.
Not if you want to make the informed quality decision.
I observe that letters and other details become grainy.
Its a shame that PNG doesn't define a 'text" chunk the way that HTML does, or the other "XML" like standards such as SVG. NAPLPS, a sort-of precursor to HTML in some ways was very text oriented and also had 'text' chunks. https://en.wikipedia.org/wiki/NAPLPS
Try DjVu, then. It renders letters precisely and with as much compression as jpeg. -- Cheers / Saludos, Carlos E. R. (from 13.1 x86_64 "Bottle" at Telcontar)