[OT] JPEG + graphs == hideous
Posted Jan 11, 2008 6:42 UTC (Fri) by roelofs
In reply to: [OT] JPEG + graphs == hideous
Parent article: What is RCU? Part 2: Usage
For xfig, how about this .gif, as opposed to the six-times-bigger .jpg?
Indeed--and notice how the red dashed line is so much brighter now, and the black-on-green text is far sharper? JPEG hates sharp boundaries. (Gibbs' phenomenon and all.)
For gnuplot, how about this .gif, as opposed to the nine-times-bigger .jpg?
You (or gnuplot) must have used a very high quality setting for the JPEG, because that nine-times-bigger JPEG is actually grayscale (i.e., nominally one-third the raw data, or at least one-half given the usual YCbCr subsampling of the color channels in a three-component JPEG). Indeed, it's so high-quality that it has only four gray shades in it (two white, two black) and is visibly flawless even to my eye.
Just for jollies, I converted your images to PNG (gif2png -s rwlock*.gif) and then ran them through pngcrush (pngcrush -brute -e -crb.png -rem alla rwlock*.png). Here are the results:
44965 Jan 10 21:13 rwlockRCUupdate.jpg // 24-bit, 504 x 350 (xfig)
7266 Jan 10 21:10 rwlockRCUupdate.gif // 3-bit palette
3350 Jan 10 22:13 rwlockRCUupdate.png // 4-bit palette (gif2png)
2867 Jan 10 22:13 rwlockRCUupdate-crb.png // 4-bit palette (pngcrush)
45664 Jan 10 21:22 rwlockRCUperfwtPREEMPT.jpg // 8-bit, 640 x 480 (gnuplot)
4940 Jan 10 21:22 rwlockRCUperfwtPREEMPT.gif // 1-bit palette
3326 Jan 10 22:13 rwlockRCUperfwtPREEMPT.png // 1-bit grayscale (gif2png)
2967 Jan 10 22:13 rwlockRCUperfwtPREEMPT-crb.png // 1-bit grayscale (pngcrush)
In short, more than a factor of 15 smaller than the JPEGs, yet perfect quality. (These are the kinds of images for which PNG was designed.)
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