[fix] Make scale dependent visibility more robust when handling non-round scales (denominators) #58968
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…dent visibility: support inclusive behavior and handle exclusive/inclusive behavior on edge cases (non-round numbers)
…ndent visibility: support inclusive behavior and handle exclusive/inclusive behavior on edge cases (non-round numbers)
…dependent visibility: handle exclusive/inclusive behavior on edge cases (non-round numbers)
…id of the 'scale * SCALE_PRECISION' expression to set (visible) layer scale. We now move to layer->minimumScale - 1, which is assured to be in the scale range, since we'll only show the 'Zoom to Visible Scale' option if scale is not in range and there IS a range difference equal to or greater than 1.
…t visibility became more robust on range limits (namely, on non-round numbers).
…eaterThanMinimumScale to make robust checks between map scale and maximum/minimum rendering scales in a scale dependent visibility context, taking non-round scales (denominators)
…rThanMinimumScale
gacarrillor
added
Map and Legend
nyalldawson
reviewed
Oct 4, 2024
| * | ||
| * \since QGIS 3.40 | ||
| */ | ||
| CORE_EXPORT bool qgsEqualToOrGreaterThanMinimumScale( const double scale, const double minScale ); |
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Could this be moved to static function in a "QgsScaleUtils" class instead?
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Follow-up b8f9760
Since the map scale (denominator) is a double, it could be a non-round number, which needs to be considered when comparing scales for scale dependent visibility of features, labels, diagrams, and the like. This should be done for both range limits: minimum (exclusive) and maximum (inclusive) scales.
This PR:
qgsDoubleNear()for equal checks, thus taking non-round scales into account.Qgis::SCALE_PRECISIONworkaround.QgsMapLayer->isInRange().equalToOrGreaterThanMinimumScale()andlessThanMaximumScale()to make scale conditions more readable, with corresponding tests.Sample of inconsistent behavior fixed by this PR:
Map layer
Expected: Layer shouldn't be rendered if map scale is a non-round number equals to layer's
minimumScale(exclusive).Current (screenshot): Range: 25000-50000, map scale: 49999,999999999716. The layer is rendered.
Note the map scale combobox shows 50000 as the current map scale (denominator).
Rule-based labeling
Expected: Labels within a rule should be rendered if map scale is a non-round number equals to rule's
maximumScale(inclusive).Current (screenshot): Rule's scale range: 50000-100000, map scale: 49999.99999999976. The labels are not rendered.
Note the map scale combobox shows 50000 as the current map scale (denominator).
Similar issues can be reproduced for rule-based rendering.
Note: Those non-round map scales can be consistently obtained by resizing the QGIS main window (Ubuntu Linux) and resetting the scale to a round number via main Scale combobox. Users think the scale is still round (according to the combobox), but internally, it's a non-round number (in practice, equal to the round one).
Making scale depentent visibility more robust when handling non-round numbers would also cover use cases where, e.g., plugin devs set non-round scales via PyQGIS, as a result of a calculation.
Additional fixes:
Fix #58150
Other users have reported this longstanding issue, for instance:
#2863 (comment)
#42443