e-book viewer: images don't resize according the zoom factor

[dmonasse]

In the e-book viewer, although I define the width, height and vertical-align of an image in "em" (and not in pixels), when I click on one of the two buttons "bigger" or "smaller", the images don't resize in accordance with the size of the font. It seems that e-book viewer does not update the em when you change the zoom factor (it works well by example in iBooks or Gitden Reader).

Is it a bug or a feature?

Thanks for all.

Denis

[DoctorOhh]

Originally Posted by dmonasse

In the e-book viewer, although I define the width, height and vertical-align of an image in "em" (and not in pixels), when I click on one of the two buttons "bigger" or "smaller", the images don't resize in accordance with the size of the font.

The two buttons are Increase font size and Decrease font size. There is no on the fly image zoom in the viewer. You can enter a custom css in the viewer preferences that could in theory zoom all images by 150%. I am not a html / css expert so you would have to research that aspect.

[kovidgoyal]

If you want to see a zoomed up version of the image, right click on it and choose to open it in a separate window.

[DoctorOhh]

Originally Posted by kovidgoyal

If you want to see a zoomed up version of the image, right click on it and choose to open it in a separate window.

Thanks for the tip.

[dmonasse]

Sorry, but that does not solve my problem. I insert in the text some images (by example mathematical formulas when I don't want to use MathML) an it is critical that, when I apply a zoom factor to the font, the same zoom factor applies to the image (that's the reason why I set the sizes of the image in em and not in pixel). I think it is natural that when I change the size of the fonts, the em change accordingly, don't you think so? Chrome, Firefox, iBooks and Gitden Reader work in this way.

Thanks for all (and for your quick response).

Denis

[DoctorOhh]

Do you realize that Kovid's answer allows you to zoom in on any image? It may not be your ideal but it does work well.

[dmonasse]

Do not get angry. I appreciate very much Kovid's work. It was just a suggestion and I was not aggressive. If some day .....

[DoctorOhh]

Originally Posted by dmonasse

Do not get angry. ... I was not aggressive.

Extremely peculiar reaction.

[Dopedangel]

Originally Posted by DoctorOhh

Extremely peculiar reaction.

Uncalled for post sorry was in a mood took it out on you

[DoctorOhh]

Originally Posted by Dopedangel

Not really I felt you were a bit rude.

......

Originally Posted by Dopedangel

OP got an answer from Kovid was not satisfied with it.

My point was one of clarification. When you follow Kovid's advice the image does not zoom by itself. I simply inquired if he realized that once opened in the other window that the image can indeed be zoomed to any size required. And since he never answered my question I still do not know if he is aware of this fact.

Originally Posted by Dopedangel

Your input was not required.

So you are the arbitrator of what is and is not required? Good to know.

[dmonasse]

I don't want any polemic and I understand that, in the Navy, the language may be a bit rude. I'm just a mathematics and computer science teacher and perhaps my english is not so good (I never learnt it at school, just german, latin and greek). Sorry for the inconvenience.

But I have to explain precisely my difficulties. I insert in the text some images (mathematical or chemical formulas, and so on). By example, look at the following in ebook viewer without zooming:



If I apply a positive zooming, I obtain the following result:



and with a negative zooming



Look at the html original code

Soit <span style='display:inline-block; vertical-align:-0.211em; width:5.263em; height:1.105em;'><img src='exosetoiles_pict_463.png' style='width:100%;'/></span>. On suppose que tous les coefficients de <span style='display:inline-block; vertical-align:0.000em; width:0.711em; height:0.895em;'><img src='exosetoiles_pict_18.png' style='width:100%;'/></span> sont des entiers naturels et que
l'ensemble <span style='display:inline-block; vertical-align:-0.316em; width:13.816em; height:1.316em;'><img src='exosetoiles_pict_464.png' style='width:100%;'/></span> est fini. 
Montrer que <span style='display:inline-block; vertical-align:0.000em; width:0.711em; height:0.895em;'><img src='exosetoiles_pict_18.png' style='width:100%;'/></span> est une matrice de permutation.

(This code is a bit tricky to bypass a bug in iBooks: iBooks don't respect the dimensions of the images, but he respects the dimensions of the spans)

As you see, zooming the image in another window is not always the solution.

Thanks in advance for any help.

Denis

[BetterRed]

Originally Posted by dmonasse

I don't want any polemic and I understand that, in the Navy, the language may be a bit rude. I'm just a mathematics and computer science teacher and perhaps my english is not so good (I never learnt it at school, just german, latin and greek). Sorry for the inconvenience.

But I have to explain precisely my difficulties. I insert in the text some images (mathematical or chemical formulas, and so on). By example, look at the following in ebook viewer without zooming:

...

Thanks in advance for any help. Denis

@dmonasse - If you prefer to read EPUB's with a program other than the calibre ebook-viewer program then associate the EPUB file type with your program of choice in your OS, and uncheck EPUB in the Preferences->Behaviour->Use internal viewer for: list.

This optional calibre PI ==>> [GUI Plugin] Open With (← click) provides the wherewithal to open file types in alternate programs (including jpeg for the editing of covers), its similar in function to the Windows Open With, with the added feature that they can be given keyboard shortcuts. I have Sigil, ADE and EPUBReader (firefox extension) in there for EPUB; if/when I can figure out how, I'll have Readium (chrome extension) in there too

There are web sites that will convert an image of a formula to mathML, I've used them a couple of times with some success.

Disassociating images from the adjacent text into a separate window also doesn't work effectively for traditional graphs and infographs. But it is good for maps because one often wants to refer to them repeatedly. However, I would prefer that my default image viewer be used rather than the one provided by calibre.

BR

[PeterT]

Wouldn't you be best finding a TrueType font that included all the math symbols and just using that instead of images?

[DoctorOhh]

Originally Posted by dmonasse

I don't want any polemic and I understand that, in the Navy, the language may be a bit rude. I'm just a mathematics and computer science teacher and perhaps my english is not so good (I never learnt it at school, just german, latin and greek). Sorry for the inconvenience.

No need to apologize. I didn't think you were rude that is why I said peculiar response because I didn't understand the context.

Originally Posted by dmonasse

But I have to explain precisely my difficulties. I insert in the text some images (mathematical or chemical formulas, and so on). By example, look at the following in ebook viewer without zooming:

I understood your problem. If you are using Calibre's viewer Kovid stated that you can right click on the actual image and open it in a new window. Once the new window is opened you can zoom the image larger as needed. On my system I use the scroll wheel on the mouse to zoom the image. Or I can use Ctrl+ or Ctrl- to zoom in or zoom out of the image. This isn't ideal but it should let you view the formulas easier.

BetterRed offers an excellent alternative, explaining how to open your book in another program that might suit your needs better.

Good Luck.

[dmonasse]

I understand. I will advise readers of the books from my publisher house to use Readium instead Calibre on a computer. It's a shame because in many ways Calibre is much better. I didn't believe it was so difficult to correct this point of detail: redefine the "em" to make it coherent with the font size. I understand that Kovid has many other things to do. May be in the future? Thanks for all.