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Windowing: Allow window to keep repainting when mouse is held in capt…
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…ion area
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@reuk
reuk committed Jul 29, 2024
1 parent ce7bafc commit 9817a2b
Showing 1 changed file with 76 additions and 36 deletions.
112 changes: 76 additions & 36 deletions modules/juce_gui_basics/native/juce_Windowing_windows.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2702,13 +2702,46 @@ class HWNDComponentPeer final : public ComponentPeer
client,
};

void doMouseMove (Point<float> position, bool isMouseDownEvent, WindowArea area)
{
std::optional<LRESULT> doMouseMove (LPARAM lParam, bool isMouseDownEvent, WindowArea area)
{
auto point = getPOINTFromLParam (lParam);

if (area == WindowArea::client)
ClientToScreen (hwnd, &point);

const auto adjustedLParam = MAKELPARAM (point.x, point.y);

// Check if the mouse has moved since being pressed in the caption area.
// If it has, then we defer to DefWindowProc to handle the mouse movement.
// Allowing DefWindowProc to handle WM_NCLBUTTONDOWN directly will pause message
// processing (and therefore painting) when the mouse is clicked in the caption area,
// which is why we wait until the mouse is *moved* before asking the system to take over.
// Letting the system handle the move is important for things like Aero Snap to work.
if (captionMouseDown.has_value() && *captionMouseDown != adjustedLParam)
{
captionMouseDown.reset();

// When clicking and dragging on the caption area, a new modal loop is started
// inside DefWindowProc. This modal loop appears to consume some mouse events,
// without forwarding them back to our own window proc. In particular, we never
// get to see the WM_NCLBUTTONUP event with the HTCAPTION argument, or any other
// kind of mouse-up event to signal that the loop exited, so
// ModifierKeys::currentModifiers gets left in the wrong state. As a workaround, we
// manually update the modifier keys after DefWindowProc exits, and update the
// capture state if necessary.
const auto result = DefWindowProc (hwnd, WM_NCLBUTTONDOWN, HTCAPTION, adjustedLParam);
getMouseModifiers();
releaseCaptureIfNecessary();
return result;
}

const auto position = getLocalPointFromScreenLParam (adjustedLParam);

ModifierKeys modsToSend (ModifierKeys::currentModifiers);

// this will be handled by WM_TOUCH
if (isTouchEvent() || areOtherTouchSourcesActive())
return;
return {};

if (! isMouseOver)
{
Expand Down Expand Up @@ -2738,7 +2771,7 @@ class HWNDComponentPeer final : public ComponentPeer
else if (! isDragging)
{
if (! contains (position.roundToInt(), false))
return;
return {};
}

static uint32 lastMouseTime = 0;
Expand All @@ -2753,6 +2786,8 @@ class HWNDComponentPeer final : public ComponentPeer
doMouseEvent (position, MouseInputSource::defaultPressure,
MouseInputSource::defaultOrientation, modsToSend);
}

return {};
}

void updateModifiersFromModProvider() const
Expand All @@ -2775,7 +2810,7 @@ class HWNDComponentPeer final : public ComponentPeer
ReleaseCapture();
}

void doMouseDown (Point<float> position, const WPARAM wParam, WindowArea area)
void doMouseDown (LPARAM lParam, const WPARAM wParam, WindowArea area)
{
// this will be handled by WM_TOUCH
if (isTouchEvent() || areOtherTouchSourcesActive())
Expand All @@ -2784,14 +2819,16 @@ class HWNDComponentPeer final : public ComponentPeer
if (GetCapture() != hwnd)
SetCapture (hwnd);

doMouseMove (position, true, area);
doMouseMove (lParam, true, area);

if (isValidPeer (this))
{
updateModifiersWithMouseWParam (wParam);

isDragging = true;

const auto position = area == WindowArea::client ? getPointFromLocalLParam (lParam)
: getLocalPointFromScreenLParam (lParam);
doMouseEvent (position, MouseInputSource::defaultPressure);
}
}
Expand Down Expand Up @@ -3730,6 +3767,34 @@ class HWNDComponentPeer final : public ComponentPeer
return ModifierKeys::currentModifiers;
}

std::optional<LRESULT> onNcLButtonDown (WPARAM wParam, LPARAM lParam)
{
handleLeftClickInNCArea (wParam);

switch (wParam)
{
case HTCLOSE:
case HTMAXBUTTON:
case HTMINBUTTON:
// The default implementation in DefWindowProc for these functions has some
// unwanted behaviour. Specifically, it seems to draw some ugly grey buttons over
// our custom nonclient area, just for one frame.
// To avoid this, we handle the message ourselves. The actual handling happens
// in WM_NCLBUTTONUP.
return 0;

case HTCAPTION:
// The default click-in-caption handler appears to block the message loop until a
// mouse move is detected, which prevents the view from repainting. We want to keep
// painting, so log the click ourselves and only defer to DefWindowProc once the
// mouse moves with the button held.
captionMouseDown = lParam;
return 0;
}

return {};
}

LRESULT peerWindowProc (HWND h, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
Expand Down Expand Up @@ -3887,10 +3952,7 @@ class HWNDComponentPeer final : public ComponentPeer
//==============================================================================
case WM_NCMOUSEMOVE:
case WM_MOUSEMOVE:
doMouseMove (message == WM_MOUSEMOVE ? getPointFromLocalLParam (lParam) : getLocalPointFromScreenLParam (lParam),
false,
message == WM_MOUSEMOVE ? WindowArea::client : WindowArea::nonclient);
return 0;
return doMouseMove (lParam, false, message == WM_MOUSEMOVE ? WindowArea::client : WindowArea::nonclient).value_or (0);

case WM_POINTERLEAVE:
case WM_NCMOUSELEAVE:
Expand All @@ -3901,7 +3963,7 @@ class HWNDComponentPeer final : public ComponentPeer
case WM_LBUTTONDOWN:
case WM_MBUTTONDOWN:
case WM_RBUTTONDOWN:
doMouseDown (getPointFromLocalLParam (lParam), wParam, WindowArea::client);
doMouseDown (lParam, wParam, WindowArea::client);
return 0;

case WM_LBUTTONUP:
Expand Down Expand Up @@ -4196,31 +4258,8 @@ class HWNDComponentPeer final : public ComponentPeer

case WM_NCLBUTTONDOWN:
{
handleLeftClickInNCArea (wParam);

// The default implementation in DefWindowProc for these functions has some
// unwanted behaviour. Specifically, it seems to draw some ugly grey buttons over
// our custom nonclient area, just for one frame.
// To avoid this, we handle the message ourselves. The actual handling happens
// in WM_NCLBUTTONUP.
if (wParam == HTCLOSE || wParam == HTMAXBUTTON || wParam == HTMINBUTTON)
return 0;

// When clicking and dragging on the caption area, a new modal loop is started
// inside DefWindowProc. This modal loop appears to consume some mouse events,
// without forwarding them back to our own window proc. In particular, we never
// get to see the WM_NCLBUTTONUP event with the HTCAPTION argument, or any other
// kind of mouse-up event to signal that the loop exited, so
// ModifierKeys::currentModifiers gets left in the wrong state. As a workaround, we
// manually update the modifier keys after DefWindowProc exits, and update the
// capture state if necessary.
if (wParam == HTCAPTION)
{
const auto result = DefWindowProc (h, message, wParam, lParam);
getMouseModifiers();
releaseCaptureIfNecessary();
return result;
}
if (auto result = onNcLButtonDown (wParam, lParam))
return *result;

break;
}
Expand Down Expand Up @@ -4616,6 +4655,7 @@ class HWNDComponentPeer final : public ComponentPeer
std::optional<TimedCallback> monitorUpdateTimer;

std::unique_ptr<RenderContext> renderContext;
std::optional<LPARAM> captionMouseDown;

//==============================================================================
JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (HWNDComponentPeer)
Expand Down

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