Viewer::keyPressEvent()'s and MagnifyingGlass::keyPressEvent()'s custom
matching of these shortcuts is the same as
MainWindowViewer::keyPressEvent()'s before the recent commit
"Reader: make 3 keyboard shortcuts work with non-Latin layouts". That
commit's message details the issues with the custom code.
The Magnifying glass actions are now enabled/disabled when
loadedComicActions are enabled/disabled - for the same reason (see the
recent "Reader: make 12 keyboard shortcuts work with non-Latin layouts"
commit). In addition, Viewer::keyPressEvent() propagated the Magnifying
glass shortcuts to MagnifyingGlass only when it was visible. Therefore
showing/hiding Magnifying glass also enables/disables these actions.
Note that Viewer::showMagnifyingGlass() shows Magnifying glass only if
render->hasLoadedComic() returns true, so
MainWindowViewer::setMglassActionsEnabled slot can be connected directly
to Viewer::magnifyingGlassVisibilityChanged signal without checking this
condition again.
MagnifyingGlass::sizeUp() and MagnifyingGlass::sizeDown() grow/shrink
both width and height, but check only width's limits. Thus the user can
first increase Magnifying glass's height, then increase its size and
make the height greater than the main window's height. The user can also
first increase the width, then decrease the size until the height
shrinks to 0 and Magnifying glass disappears.
When Magnifying glass disappears, the only way to make it visible again
is to restore its default size by restarting YACReader, because the
invisible MagnifyingGlass widget does not receive wheel events and
Viewer::keyPressEvent() propagates shortcuts to mglass only if it is
visible. And even this workaround is possible only because YACReader
does not save/restore Magnifying glass's size (should it?).
Always checking both width and height limits fixes the bug. If one of
the dimensions reaches a limit, only the other dimension is modified. If
both dimensions reach their limits, neither is modified.
qobject_cast<const Viewer *> improves const correctness.
QLabel::pixmap() is const-qualified => make Viewer::pixmap() const too.
Return non-const QPixmap from Viewer::pixmap() to let compiler move the
return value at the function's call sites.
Introduce a named constant maxRelativeDimension. Change its type from
float to double, which usually multiplies faster on x86-64.
Remove redundant parentheses to improve readability.
Not all possible keyboard modifiers of a wheel event change
MagnifyingGlass's pixmap. So in case of e.g. MetaModifier or more than
one modifier, MagnifyingGlass::wheelEvent() calls updateImage() to no
avail.
Move the updateImage() call into the public slots to make them
self-sufficient. This also allows not to call updateImage() when the
pixmap is not changed in case the adjusted parameter has reached its
minimum or maximum value already.
const QPixmap should perform as fast as a pointer
there is a replacement version for Qt5 but it requires Qt5.15, so we are using indirection witch is unsafer but it should be ok as all the action is happen in the main thread
