QGIS » QGIS Application

Hello everybody,
this is my first post, sorry if it is too big,
I am geologist/ petrologist and use QGIS not only for mapping big and large features as geological complexes, but also I use it to map thin sections (thin slabs of rock normally 3x4.5cm size). I find getting all work done in gis for this tiny scale objects very productive, as I can interpolate data obtained in very small scale to huge area seamlessly. Qgis main canvas with scale bar and scale widget gets it very right (ability to set scale bellow 1:1, i.e. 100:1, scale bar down to mm units). However with these thin section and other layered microscopy pictures + vector data I run into total nightmare in QGIS composer.

Scale can't be set bellow 2:1, anything bellow gets nullified -> 0, and if you click anywhere to stop the cursor blinking or simply to do next action (for example export to pdf, image etc.), whole world collapses into "singularity" (map gets 0 scale applied, that means it's left margin are same as right, and up is same as low boundary) "... It is worth mentioning that somehow it does round up numbers to integer in ScaleLineEdit field after applying scale to view, but for interval from 0.5-0.9(9) it always sets visible magnification to exactly 1 (so 2:1 manually is unobtainable). If value <0.5 are inputed, then after scaling the view, field does not get deactivated, also it makes number rounded down to '0' and cursor keeps blinking (prepared to jump to singularity). If 0 scale was just applied, (for example just clicking anywhere else or while it is 0 and not blinking, clicking "Update preview") there is one clear way to crash/loop qgis - trying to set scale changing 0 into anything but not 0 (negative numbers hangs too). To get out of "singularity" there is few ways: a) change in Map item properties -> extent fields; b) delete map and create new. However Composer will get weird if there was scale bar used while getting to "singularity" -> a) if You delete map, scale lefts on sheet with one end on it and other going to "singularity" (I guess to 0,0 of CRS) and is unable to be selected and deleted; b) if recovering from "singularity" with changing map extent, scale bar recovers too, but it leaves some artifacts, and Qgis Printing Composer window starts to behave weird: while sliding, slide bars goes to wrong directions (it tries to leave the screen going to left).
My suggestion would be to get rid of that rounding "feature" and make it possible to enter double numbers and keep it, so that scale would never go to 0 (I think I saw that 0 even in the code). This is printing composer, and even if people less crazy than me are working in scales from 1:50 to 1:1 it does really big difference if it is 1:1 or 1:1.5. I think It would brake scale bar having numerical form (I am not sure, but I guess that is why it gets rounded at all: just to be inserted to '1:'[scale]...) I would understand if most of people would want to keep it as is, and for now I can get things nearly done while even not touching scale field, for example with changing map extent or using atlas generator (that's now the most robust way of dealing with problem). Could that part be reworked? (I could try of doing it)