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April 11, 2016 05:27
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A shell script (employing ImageMagick) to generate 1x and 2x image fragments with JPEG quality at 90, 50 and 20. Source: http://www.html5rocks.com/en/mobile/high-dpi/#toc-tech-overview
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| #!/usr/bin/env bash | |
| QUAL_HI=90 | |
| QUAL_MID=50 | |
| QUAL_LOW=20 | |
| ORIG=hq2x.jpg | |
| # Create 2x version. | |
| convert original.jpg -quality $QUAL_HI hq2x.jpg | |
| # Create 1x version. | |
| convert hq2x.jpg -resize 50% hq1x.jpg | |
| # Create compressed versions. | |
| convert hq2x.jpg -quality $QUAL_MID lq2x.jpg | |
| convert hq1x.jpg -quality $QUAL_MID lq1x.jpg | |
| # Create very compressed versions. | |
| convert hq2x.jpg -quality $QUAL_LOW ulq2x.jpg | |
| convert hq1x.jpg -quality $QUAL_LOW ulq1x.jpg | |
| # Crop everything into little samples for clarity. | |
| for img in *1x.jpg | |
| do | |
| convert $img -crop 160x120+0+0 preview/$img; | |
| done | |
| for img in *2x.jpg | |
| do | |
| convert $img -crop 320x240+0+0 preview/$img; | |
| done | |
| # Tile into a preview. | |
| montage -label '%f, %b -- quality: %Q' preview/*x.jpg -shadow -border 5 -geometry 320x240+5+5 preview/tile.jpg |
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