Thank you for your answer, Miklós!
Before posting my question yesterday, I had been thinking along similar lines. However, I was a bit confused about how and in what order the event handlers PanelMoveEntered, PanelMoved, PanelMoveExited, PanelResizedEntered, PanelResized, and PanelResizedExited are actually triggered. During a docking transition, for example, these handlers may be called multiple times until the docking or undocking operation is complete, and while debugging I noticed that their sequence was not always consistent. This made it quite difficult for me to reliably track the events.
In the end, I came up with a solution similar to the one you mentioned: I needed to rely on multiple event handlers, and when switching from one docked orientation to another, I tested the equality of two corner points relative to the reference rectangle. This helped me avoid false signals in cases where a docked palette was simply being resized in its current docked state.
At the moment I am still experimenting with this approach. I would be glad to hear any feedback or suggestions. And of course, thank you — I truly appreciate the time you took to answer my question.
//-------
// header
//-------
class MyPalette final :
public DG::Palette,
public DG::PanelObserver,
public DG::CompoundItemObserver
private:
DG::NativeRect referenceRectangle;
bool wasPreviouslyDocked = false;
bool dockStateOrOrientationHasChanged = false;
// ...
int GetCoincidingCornerCountOfTwoScreenSpaceRectangles (const DG::NativeRect& r1, const DG::NativeRect& r2) const;
void PanelMoved (const DG::PanelMoveEvent& event) override;
void PanelMoveExited (const DG::PanelMoveEvent& event) override;
void PanelResized (const DG::PanelResizeEvent& event) override;
// ...
public:
// constructor
MyPalette ();
// ...
};
//-------
// source
//-------
int MyPalette::GetCoincidingCornerCountOfTwoScreenSpaceRectangles (const DG::NativeRect& r1, const DG::NativeRect& r2) const
{
int count = 0;
if (r1.GetLeftTop () == r2.GetLeftTop ()) ++count;
if (r1.GetRightTop () == r2.GetRightTop ()) ++count;
if (r1.GetLeftBottom () == r2.GetLeftBottom ()) ++count;
if (r1.GetRightBottom () == r2.GetRightBottom ()) ++count;
return count;
}
MyPalette::MyPalette () :
DG::Palette (ACAPI_GetOwnResModule (), ID_ADDON_PALETTE, ACAPI_GetOwnResModule (), paletteGuid),
{
Attach (*this);
AttachToAllItems (*this);
BeginEventProcessing ();
// ...
wasPreviouslyDocked = IsDocked ();
referenceRectangle = GetReferenceRectangleInScreenSpace ();
}
void MyPalette::PanelMoved (const DG::PanelMoveEvent& /*event*/)
{
// note that PanelMove may be called multiple times during docking transitions...
dockStateOrOrientationHasChanged =
(wasPreviouslyDocked != IsDocked () ||
(wasPreviouslyDocked && IsDocked () && CoincidingCornerCountOfTwoScreenSpaceRectangles (referenceRectangle, GetReferenceRectangleInScreenSpace ()) < 2));
}
void MyPalette::PanelMoveExited (const DG::PanelMoveEvent& /*event*/)
{
dockStateOrOrientationHasChanged =
(wasPreviouslyDocked != IsDocked () ||
(wasPreviouslyDocked && IsDocked () && CoincidingCornerCountOfTwoScreenSpaceRectangles (referenceRectangle, GetReferenceRectangleInScreenSpace ()) < 2));
if (dockStateOrOrientationHasChanged) {
PerformDockStateTransitionRelatedOperations ();
}
}
void MyPalette::PanelResized (const DG::PanelResizeEvent& event)
{
const short horizontalChange = event.GetHorizontalChange ();
const short verticalChange = event.GetVerticalChange ();
if (horizontalChange == 0 && verticalChange == 0) {
return;
}
BeginMoveResizeItems ();
// usual resizing/moving operations...
EndMoveResizeItems ();
if (dockStateOrOrientationHasChanged) {
PerformDockStateTransitionRelatedOperations ();
}
}
void MyPalette::PerformDockStateTransitionRelatedOperations ()
{
// do something nice and meaningful
// ...
// then
wasPreviouslyDocked = IsDocked ();
dockStateOrOrientationHasChanged = false;
referenceRectangle = GetReferenceRectangleInScreenSpace ();
}
