On 5/17/2019 9:43 AM, Rudolf Bahr wrote:

On Thu, May 16, 2019 at 02:40:07PM +0200, Hans Hagen wrote:

...

On 5/16/2019 12:21 PM, Rudolf Bahr wrote:

...

The problem with artefacts in .png images is still unsolved for me. I can circumvent it by using .jpg or .tiff images instead of .png images as long as no transparent areas in the images are needed. As far as I know .jpg and .tiff formats cannot handle transparancy, do they?

Now in .log files messages like "luatex warning > pdfe: invalid 11 0 R object at offset 223611" can be seen. Please, what do they mean?

...

Does that come from an pdf generated by image magick>? If so, the problem is there ... the last years I've seen lots of converted files with bogus pdf objects. (Kind of harmless but still.)

Hans

No. I never use neither ImageMagick nor GraphicsMagick to generate images in .pdf-format. Even with my scanner software I produce always .jpg-images though it is capable to produce .pdf-output too. The only .pdf-files I'm doing are made by ConTeXt-LMTX!

ah, but you ask for an tiff image .. there is no native tiff support so that one gets converted to pdf beforehand ... you can see an m_k_i_v_* image in your path ... as gm is called that is the reason why you get the bad object: it really is in that pdf file

I shall append another, interesting MWE. There is a .png-image which is, as it occasionally happens, represented as it should, by ConTeXt. And then the same .png-image to which I added a red frame by GIMP2.10. This one shows artefacts in ConTeXt!

I'm adding the .log-file too. There again is a luatex-warning, as I could observe them often in ConTeXt-LMTX:

-------------------------------------------------------------- luatex warning > pdfe: invalid 11 0 R object at offset 385741 -------------------------------------------------------------- Please, what does mean it? I fear there is something wrong with the .png-handling of ConTeXt/luatex.

The outputs of feh image----red-frame.png gm display image----red-frame.png are looking ok. And GIMP2.10 has produced all image-files.

if you use luatex it will mention a mismatch between the resolutions in the different kinds of metadata (93 vs 94 pixels)

Rudolf

PS.: echo $PATH /home/sam/Android/platform-tools:/bin:/usr/bin:/home/sam/context-lmtx/tex/texmf-linux-64/bin:/home/sam/context-lmtx/bin:/home/sam/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

R.

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On Fri, 17 May 2019 09:43:29 +0200 Rudolf Bahr wrote:

And then the same .png-image to which I added a red frame by GIMP2.10. This one shows artefacts in ConTeXt!

I *always* use MetaPost to add features (and to clip) images. These features (arrows, labels, etc.) are then vectorial and easily modified through programming, for example labels can be language-dependent. -- Alan