Bug #18013: Image compositing with JPGs results in dithered output - TYPO3 Core - TYPO3 Forge

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Bug #18013

closed

Image compositing with JPGs results in dithered output

Added by Rdiger Schulz almost 17 years ago. Updated about 11 years ago.

Status:

Closed

Priority:

Should have

Assignee:

Category:

Target version:

Start date:

2008-01-17

Due date:

% Done:

Estimated time:

TYPO3 Version:

4.1

PHP Version:

5.2

Tags:

Complexity:

Is Regression:

Sprint Focus:

Description

I want to create a dynamic image, where I have a JPG as a background, and want to insert some text in the foreground:

TEASER = IMAGE
TEASER.file = GIFBUILDER
TEASER.file {
XY = 302, 282
format = jpg
quality = 100

10 = IMAGE
    10.file = fileadmin/images/teaserbild.jpg
    10.file.width = 300

20 = TEXT
    20.text = Do it!
    20.fontColor = white
    20.offset = 190,190
}

The text turns out fine, but the background image suffers from heavy dithering. Looking in the temp folders, there is GIF version of teaserbild.jpg.

This somehow seems to be related to issue 4186. I already applied the latest patch from there, and just scaling an image works fine. But not when doing a composition.

Does anybody have a suggestion on this?

Attached is the original image, and a rendered result.

The problem arouses independet of ImageMagick version; I had a 4 and a 6 on Linux and a 5 on Windows - the images always look the same (they always get converted into a GIF at one step).
(issue imported from #M7194)

Files

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teaserbild.jpg (57.8 KB) teaserbild.jpg		Administrator Admin, 2008-01-17 19:21
19816fbbb0.jpg (67.6 KB) 19816fbbb0.jpg		Administrator Admin, 2008-01-17 19:23
tt_content-menu-after-cObject.txt (1007 Bytes) tt_content-menu-after-cObject.txt		Administrator Admin, 2009-10-27 10:30
tt_content-menu-after-cObject.jpg (17.9 KB) tt_content-menu-after-cObject.jpg		Administrator Admin, 2009-10-27 10:33

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Updated by Tomas Mrozek over 16 years ago

I confirm this issue even for TYPO3 4.2.0.

It must have something to do with the images being converted first to GIF at some point and then later to JPEG. As soon as this 2 settings are present, the problem is gone:

$TYPO3_CONF_VARS['GFX']['gdlib_png'] = '1';
$TYPO3_CONF_VARS['GFX']['png_truecolor'] = '1';

Of course, this has the unwanted effect of all other images (e.g. in GMENU) being truecolor PNG.

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Updated by Leo Bossmann over 16 years ago

This issue is also present in TYPO3 4.2.1.

Setting above options for me only worked after enabling GDlib2:

$TYPO3_CONF_VARS['GFX']['gdlib_2'] = 1;

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Updated by Christopher Hlubek over 16 years ago

I can confirm this for TYPO3 4.1.7

This is very serious for most of the interesting image manipulations!

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Updated by Felix Buenemann over 15 years ago

I can confirm this, GIFBUILDER only outputs truecolor png when above settings are made. Maybe setting [FE][png_to_gif] = 1 could help remedy the generation of PNG truecolor images in the FE.

I also noticed, that the dithering done by Photoshop is far superior to the dithering by GDlib, which makes this issue even worse.

Btw. I'm using gdlib 2 (php bundled) and GraphicsMagick 1.3.3.

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Updated by Felix Buenemann over 15 years ago

I think this is related to bug id #14537 and still actual in 4.2.8.

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Updated by Thomas Deinhamer about 15 years ago

The problem occurs also for me, when using
typoscript to add a after.cObject to a menu; see
the file 'tt_content-menu-after-cObject.txt' for the details.
Consider the media-file at position 0 to be
a full-colored, high-quality jpg with high resolution.
The result is 'tt_content-menu-after-cObject.jpg'.

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