Improve DPI handling in wxSTC

Adjusting the zoom level does not work correctly. It could lead to ever
increasing zoom.
Instead, set the correct DPI of the underlying device context.

samples/stc/edit.cpp

@@ -196,7 +196,7 @@ Edit::Edit (wxWindow *parent, wxWindowID id,
 
     // miscellaneous
     m_LineNrMargin = TextWidth (wxSTC_STYLE_LINENUMBER, "_999999");
-    m_FoldingMargin = 16;
+    m_FoldingMargin = FromDIP(16);
     CmdKeyClear (wxSTC_KEY_TAB, 0); // this is done by the menu accelerator key
     SetLayoutCache (wxSTC_CACHE_PAGE);
     UsePopUp(wxSTC_POPUP_ALL);

src/stc/PlatWX.cpp

@@ -103,6 +103,8 @@ wxColour wxColourFromCDandAlpha(ColourDesired& cd, int alpha) {
 namespace
 {
 
+inline wxWindow* GETWIN(WindowID id) { return (wxWindow*)id; }
+
 // wxFont with ascent cached, a pointer to this type is stored in Font::fid.
 class wxFontWithAscent : public wxFont
 {
@@ -295,15 +297,15 @@ void SurfaceImpl::InitPixMap(int width, int height, Surface *surface, WindowID w
         hdc = new wxMemoryDC(static_cast<SurfaceImpl*>(surface)->hdc);
     else
         hdc = new wxMemoryDC();
+    ((wxMemoryDC*)hdc)->GetImpl()->SetWindow(GETWIN(winid));
     hdcOwned = true;
     if (width < 1) width = 1;
     if (height < 1) height = 1;
 #ifdef __WXMSW__
     bitmap = new wxBitmap(width, height);
-    wxUnusedVar(winid);
 #else
     bitmap = new wxBitmap();
-    bitmap->CreateScaled(width, height,wxBITMAP_SCREEN_DEPTH,((wxWindow*)winid)->GetContentScaleFactor());
+    bitmap->CreateScaled(width, height,wxBITMAP_SCREEN_DEPTH,(GETWIN(winid))->GetContentScaleFactor());
 #endif
     ((wxMemoryDC*)hdc)->SelectObject(*bitmap);
 }
@@ -999,7 +1001,6 @@ public:
 
     // helpers
     void SetFont(Font &font_);
-    void SetScale(wxDC* dc);
     HRESULT FlushDrawing();
     void D2DPenColour(ColourDesired fore, int alpha=255);
     void DrawTextCommon(PRectangle rc, Font &font_, XYPOSITION ybase,
@@ -1057,19 +1058,18 @@ SurfaceD2D::~SurfaceD2D()
     Release();
 }
 
-void SurfaceD2D::Init(WindowID WXUNUSED(wid))
+void SurfaceD2D::Init(WindowID wid)
 {
     Release();
 
-    wxScreenDC sdc;
-    SetScale(&sdc);
+    m_logPixelsY = GETWIN(wid)->GetDPI().GetY();
 }
 
 void SurfaceD2D::Init(SurfaceID sid, WindowID wid)
 {
     Release();
 
-    wxWindow* win = wxDynamicCast(wid,wxWindow);
+    wxWindow* win = GETWIN(wid);
     if ( win && win->GetName() == "wxSTCCallTip" )
         win = win->GetParent();
 
@@ -1078,7 +1078,7 @@ void SurfaceD2D::Init(SurfaceID sid, WindowID wid)
     {
         wxDC* const dc = static_cast<wxDC*>(sid);
         const wxSize sz = dc->GetSize();
-        SetScale(dc);
+        m_logPixelsY = win->GetDPI().GetY();
         ScintillaWX* const
             sciwx = reinterpret_cast<ScintillaWX*>(stc->GetDirectPointer());
         m_surfaceData = static_cast<SurfaceDataD2D*>(sciwx->GetSurfaceData());
@@ -1773,12 +1773,6 @@ void SurfaceD2D::SetFont(Font &font_)
     }
 }
 
-void SurfaceD2D::SetScale(wxDC* dc)
-{
-    wxSize sz = dc->GetPPI();
-    m_logPixelsY = sz.GetY();
-}
-
 HRESULT SurfaceD2D::FlushDrawing()
 {
     return m_pRenderTarget->Flush();
@@ -1861,8 +1855,6 @@ Surface *Surface::Allocate(int technology) {
 //----------------------------------------------------------------------
 
 
-inline wxWindow* GETWIN(WindowID id) { return (wxWindow*)id; }
-
 Window::~Window() {
 }
 

src/stc/ScintillaWX.cpp

@@ -1039,7 +1039,7 @@ void ScintillaWX::DoGainFocus(){
     CreateSystemCaret();
 }
 
-void ScintillaWX::DoSysColourChange() {
+void ScintillaWX::DoInvalidateStyleData() {
     InvalidateStyleData();
 }
 

src/stc/ScintillaWX.h

@@ -161,7 +161,7 @@ public:
     void DoSize(int width, int height);
     void DoLoseFocus();
     void DoGainFocus();
-    void DoSysColourChange();
+    void DoInvalidateStyleData();
     void DoLeftButtonDown(Point pt, unsigned int curTime, bool shift, bool ctrl, bool alt);
     void DoRightButtonDown(Point pt, unsigned int curTime, bool shift, bool ctrl, bool alt);
     void DoLeftButtonUp(Point pt, unsigned int curTime, bool ctrl);

src/stc/stc.cpp

@@ -240,18 +240,6 @@ bool wxStyledTextCtrl::Create(wxWindow *parent,
     SetFontQuality(wxSTC_EFF_QUALITY_DEFAULT);
 #endif
 
-#ifdef __WXMSW__
-    // Set initial zoom for active DPI
-    const HDC hdc = ::GetDC(parent->GetHWND());
-    const int baseDPI = ::GetDeviceCaps(hdc, LOGPIXELSY);
-    const int activeDPI = parent->GetDPI().y;
-    ::ReleaseDC(parent->GetHWND(), hdc);
-
-    const int ptSizeOld = StyleGetSize(wxSTC_STYLE_DEFAULT);
-    const int ptSizeNew = (int)wxMulDivInt32(ptSizeOld, activeDPI, baseDPI);
-    SetZoom(GetZoom() + (ptSizeNew - ptSizeOld));
-#endif
-
     return true;
 }
 
@@ -5445,12 +5433,10 @@ void wxStyledTextCtrl::OnGainFocus(wxFocusEvent& evt) {
 }
 
 
-void wxStyledTextCtrl::OnDPIChanged(wxDPIChangedEvent& evt)
-{
-    int ptSizeOld = StyleGetSize(wxSTC_STYLE_DEFAULT);
-    int ptSizeNew = (int)wxMulDivInt32(ptSizeOld, evt.GetNewDPI().y, evt.GetOldDPI().y);
-    SetZoom(GetZoom() + (ptSizeNew - ptSizeOld));
+void wxStyledTextCtrl::OnDPIChanged(wxDPIChangedEvent& evt) {
+    m_swx->DoInvalidateStyleData();
 
+    // adjust the margins to the new DPI
     for ( int i = 0; i < SC_MAX_MARGIN; ++i )
     {
         SetMarginWidth(i, (int)wxMulDivInt32(GetMarginWidth(i), evt.GetNewDPI().y, evt.GetOldDPI().y));
@@ -5459,7 +5445,7 @@ void wxStyledTextCtrl::OnDPIChanged(wxDPIChangedEvent& evt)
 
 
 void wxStyledTextCtrl::OnSysColourChanged(wxSysColourChangedEvent& WXUNUSED(evt)) {
-    m_swx->DoSysColourChange();
+    m_swx->DoInvalidateStyleData();
 }
 
 

src/stc/stc.cpp.in

@@ -240,18 +240,6 @@ bool wxStyledTextCtrl::Create(wxWindow *parent,
     SetFontQuality(wxSTC_EFF_QUALITY_DEFAULT);
 #endif
 
-#ifdef __WXMSW__
-    // Set initial zoom for active DPI
-    const HDC hdc = ::GetDC(parent->GetHWND());
-    const int baseDPI = ::GetDeviceCaps(hdc, LOGPIXELSY);
-    const int activeDPI = parent->GetDPI().y;
-    ::ReleaseDC(parent->GetHWND(), hdc);
-
-    const int ptSizeOld = StyleGetSize(wxSTC_STYLE_DEFAULT);
-    const int ptSizeNew = (int)wxMulDivInt32(ptSizeOld, activeDPI, baseDPI);
-    SetZoom(GetZoom() + (ptSizeNew - ptSizeOld));
-#endif
-
     return true;
 }
 
@@ -972,12 +960,10 @@ void wxStyledTextCtrl::OnGainFocus(wxFocusEvent& evt) {
 }
 
 
-void wxStyledTextCtrl::OnDPIChanged(wxDPIChangedEvent& evt)
-{
-    int ptSizeOld = StyleGetSize(wxSTC_STYLE_DEFAULT);
-    int ptSizeNew = (int)wxMulDivInt32(ptSizeOld, evt.GetNewDPI().y, evt.GetOldDPI().y);
-    SetZoom(GetZoom() + (ptSizeNew - ptSizeOld));
+void wxStyledTextCtrl::OnDPIChanged(wxDPIChangedEvent& evt) {
+    m_swx->DoInvalidateStyleData();
 
+    // adjust the margins to the new DPI
     for ( int i = 0; i < SC_MAX_MARGIN; ++i )
     {
         SetMarginWidth(i, (int)wxMulDivInt32(GetMarginWidth(i), evt.GetNewDPI().y, evt.GetOldDPI().y));
@@ -986,7 +972,7 @@ void wxStyledTextCtrl::OnDPIChanged(wxDPIChangedEvent& evt)
 
 
 void wxStyledTextCtrl::OnSysColourChanged(wxSysColourChangedEvent& WXUNUSED(evt)) {
-    m_swx->DoSysColourChange();
+    m_swx->DoInvalidateStyleData();
 }