Backport: Bug [#2171]. Implement per-monitor DPI Awareness on Windows.

Backport of changeset 8244:134a3860b01e.

1 files changed, 21 insertions, 0 deletions

diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index 695371bf8..97478e872 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -95,6 +95,10 @@
 #define WM_UNICHAR                      0x0109
 #endif
 
+#ifndef WM_DPICHANGED
+#define WM_DPICHANGED 0x02E0
+#endif
+
 #ifndef UNICODE_NOCHAR
 #define UNICODE_NOCHAR                  0xFFFF
 #endif
@@ -279,6 +283,8 @@ class ScintillaWin :
 	unsigned int linesPerScroll;	///< Intellimouse support
 	int wheelDelta; ///< Wheel delta from roll
 
+	UINT dpi = 72;
+
 	HRGN hRgnUpdate;
 
 	bool hasOKText;
@@ -335,6 +341,8 @@ class ScintillaWin :
 	void AddCharUTF16(wchar_t const *wcs, unsigned int wclen, CharacterSource charSource);
 	Sci::Position EncodedFromUTF8(const char *utf8, char *encoded) const;
 
+	void CheckDpiChanged();
+
 	bool PaintDC(HDC hdc);
 	sptr_t WndPaint();
 
@@ -825,6 +833,14 @@ Sci::Position ScintillaWin::EncodedFromUTF8(const char *utf8, char *encoded) con
 	}
 }
 
+void ScintillaWin::CheckDpiChanged() {
+	const UINT dpiNow = DpiForWindow(wMain.GetID());
+	if (dpi != dpiNow) {
+		dpi = dpiNow;
+		InvalidateStyleData();
+	}
+}
+
 // Add one character from a UTF-16 string, by converting to either UTF-8 or
 // the current codepage. Code is similar to HandleCompositionWindowed().
 void ScintillaWin::AddCharUTF16(wchar_t const *wcs, unsigned int wclen, CharacterSource charSource) {
@@ -875,6 +891,7 @@ bool ScintillaWin::PaintDC(HDC hdc) {
 }
 
 sptr_t ScintillaWin::WndPaint() {
+	CheckDpiChanged();
 	//ElapsedPeriod ep;
 
 	// Redirect assertions to debug output and save current state
@@ -1874,6 +1891,10 @@ sptr_t ScintillaWin::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam
 			InvalidateStyleData();
 			break;
 
+		case WM_DPICHANGED:
+			InvalidateStyleRedraw();
+			break;
+
 		case WM_CONTEXTMENU:
 			return ShowContextMenu(iMessage, wParam, lParam);