377554 - Reduce download size by compressing PNG images

Status: VERIFIED FIXED

(Calendar :: General, enhancement)

Description

[Stefan Sitter [:ssitter]]

Reduce download size by compressing PNG images

A quick test by myself showed that the win32 Lightning xpi download size can be reduced by almost 50 kilobyte by re-compressing the PNG images using a PNG compression program like pngcrush or OptiPNG.

According to lilmatt this was already done back in 2004 for the images. The savings I measured are mostly caused by compressing the PNG images that were added for the prototype event dialog.

Comment 1

[Stefan Sitter [:ssitter]]

Attachment: zip archive with re-compressed PNG files

The following files have been compressed using OptiPNG 0.5.5 with option -o7:

    mozilla/calendar/prototypes/themes/pinstripe/*.png
    mozilla/calendar/prototypes/themes/winstripe/*.png
    mozilla/calendar/base/themes/common/*.png

lightning.xpi size before compression 1.085.440 Bytes
lightning.xpi size after compression  1.013.945 Bytes

Comment 2

[Michael Büttner (no reviews TFN)]

Comment on attachment 261598 [details]
zip archive with re-compressed PNG files

r=mickey

Comment 3

[Simon Paquet [:sipaq]]

Updated images checked in.

Comment 4

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

Attachment: zip archive with (even-better) compressed PNG files

Using a combination of brute force methods via PNGGauntlet and PNGOut here's a .zip archive that offers an additional 8% decrease in file size.

Comment 5

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

More stats:

Stefan's uncompressed archive size: 288,120 bytes
My uncompressed archive size: 265,074 bytes

Saving 23,046 bytes, or 8%.

Comment 6

[Martin Schröder [:mschroeder]]

Mickey, you are the reviewer. :) Do we want further size reduction of PNG images?

Comment 7

[Michael Büttner (no reviews TFN)]

Comment on attachment 271020 [details]
zip archive with (even-better) compressed PNG files

I went through the images and took some random samples. Since I couldn't find any difference in image quality -> r=mickey.

It's probably a good idea to document which tool with which parameters has been used to compress the images, since they will most probably change in the future.

Comment 8

[Michael Büttner (no reviews TFN)]

Christian, which of these compressed images do you want to take? I'd just take the smaller one, but the final choice is up to you.

Comment 9

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

Hey people,

I just used PNGGauntlet available at 

http://brh.numbera.com/software/pnggauntlet/

And overwrote the old PNGOut file provided with the latest version. Then I enabled the "Brute Force" option in PNGGauntlet and out came the "slightly better" compressed files.

Hope this helps.

Comment 10

[Martin Schröder [:mschroeder]]

Cc'ing Christian to answer comment#8.

Comment 11

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

don't think this can make 0.7, maybe 0.8 instead.

Comment 12

[Stefan Sitter [:ssitter]]

This bug is already resolved as fixed for 0.7. If there is more work to be done this bug should be reopened or a new bug should be filed.

Comment 13

[Martin Schröder [:mschroeder]]

Comment on attachment 271020 [details]
zip archive with (even-better) compressed PNG files

Marking obsolete. The bug is already closed and these  images got never checked in.