Fix support for high DPI icons in generic wxListCtrl

This is a cherry pick of the merge commit 5845312 (Merge branch
'generic-listctrl-hidpi-images', 2022-10-26) from master including the
following commits:

* Support high DPI bitmaps in wxGenericListCtrl.
* Rename variable to have a less confusing name.
* Add wxDrawImageBitmap() helper and use it in wx{List,Tree}Ctrl.
* Don't duplicate same code for small icon, list and report modes.

See #22907, #22916.

docs/changes.txt

@@ -255,7 +255,7 @@ All (GUI):
 - Improve wxWebView::RunScriptAsync() performance (Tobias Taschner, #22781).
 - Fix data race when processing events generated in a worker thread.
 - Fix compilation problem in wx/propgrid/editors.h (Loïc Bartoletti, #22875).
-- Fix wxGenericTreeCtrl icons rendering in high DPI (Gerhard Stein, #22887).
+- Fix wxGeneric{List,Tree}Ctrl high DPI icons (Gerhard Stein, #22887, #22916).
 - Add macros for event tables for missing wxWebView events (PB, #22949).
 - Improve month selection in wxGenericCalendarCtrl (Lauri Nurmi, #22853).
 - Fix maximum length of wxPropertyGrid editors (#23033).

include/wx/generic/private/drawbitmap.h

@@ -0,0 +1,41 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/generic/private/drawbitmap.h
+// Purpose:     Small helper for drawing images.
+// Author:      Vadim Zeitlin
+// Created:     2022-10-25
+// Copyright:   (c) 2022 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_GENERIC_PRIVATE_DRAWBITMAP_H_
+#define _WX_GENERIC_PRIVATE_DRAWBITMAP_H_
+
+#include "wx/dc.h"
+#include "wx/window.h"
+#include "wx/withimages.h"
+
+// Just a trivial wrapper for wxDC::DrawBitmap() using wxWithImages: this is
+// used in several places in the generic wxListCtrl and wxTreeCtrl code.
+inline void
+wxDrawImageBitmap(wxWindow* window,
+                  const wxWithImages& images,
+                  int image,
+                  wxDC& dc,
+                  int x,
+                  int y)
+{
+    dc.DrawBitmap(images.GetImageBitmapFor(window, image),
+                  x, y,
+                  true /* use mask */);
+}
+
+// Overload for the controls deriving from both wxWindow and wxWithImages, as
+// both wxListCtrl and wxTreeCtrl do.
+template <typename T>
+inline void
+wxDrawImageBitmap(T* window, int image, wxDC& dc, int x, int y)
+{
+    wxDrawImageBitmap(window, *window, image, dc, x, y);
+}
+
+#endif // _WX_GENERIC_PRIVATE_DRAWBITMAP_H_

include/wx/generic/private/listctrl.h

@@ -640,7 +640,7 @@ class wxListMainWindow : public wxWindow
     void DrawImage( int index, wxDC *dc, int x, int y );
     void GetImageSize( int index, int &width, int &height ) const;
 
-    void SetImageList( wxImageList *imageList, int which );
+    void SetImages( wxWithImages *images, const int which );
     void SetItemSpacing( int spacing, bool isSmall = false );
     int GetItemSpacing( bool isSmall = false );
 
@@ -694,8 +694,9 @@ class wxListMainWindow : public wxWindow
         SetItem( info );
     }
 
-    wxImageList* GetSmallImageList() const
-        { return m_small_image_list; }
+    wxWithImages* GetSmallImages() const
+        { return m_small_images; }
+
 
     // set the scrollbars and update the positions of the items
     void RecalculatePositions();
@@ -811,8 +812,9 @@ class wxListMainWindow : public wxWindow
     bool                 m_dirty;
 
     wxColour            *m_highlightColour;
-    wxImageList         *m_small_image_list;
-    wxImageList         *m_normal_image_list;
+    wxWithImages        *m_small_images;
+    wxWithImages        *m_normal_images;
+
     int                  m_small_spacing;
     int                  m_normal_spacing;
     bool                 m_hasFocus;

src/generic/listctrl.cpp

@@ -35,6 +35,8 @@
 
 #include "wx/imaglist.h"
 #include "wx/renderer.h"
+
+#include "wx/generic/private/drawbitmap.h"
 #include "wx/generic/private/listctrl.h"
 #include "wx/generic/private/widthcalc.h"
 
@@ -1118,19 +1120,19 @@ void wxListHeaderWindow::OnPaint( wxPaintEvent &WXUNUSED(event) )
         // and the width of the icon, if any
         int ix = 0, iy = 0;    // init them just to suppress the compiler warnings
         const int image = item.m_image;
-        wxImageList *imageList;
+        wxWithImages *smallImages;
         if ( image != -1 )
         {
-            imageList = m_owner->GetSmallImageList();
-            if ( imageList )
+            smallImages = m_owner->GetSmallImages();
+            if ( smallImages )
             {
-                imageList->GetSize(image, ix, iy);
+                smallImages->GetImageLogicalSize(this, image, ix, iy);
                 wLabel += ix + HEADER_IMAGE_MARGIN_IN_REPORT_MODE;
             }
         }
         else
         {
-            imageList = NULL;
+            smallImages = NULL;
         }
 
         // ignore alignment if there is not enough space anyhow
@@ -1159,16 +1161,15 @@ void wxListHeaderWindow::OnPaint( wxPaintEvent &WXUNUSED(event) )
         wxDCClipper clipper(dc, x, HEADER_OFFSET_Y, cw, h);
 
         // if we have an image, draw it on the right of the label
-        if ( imageList )
+        if ( smallImages )
         {
-            imageList->Draw
-                       (
-                        image,
-                        dc,
-                        xAligned + wLabel - ix - HEADER_IMAGE_MARGIN_IN_REPORT_MODE,
-                        HEADER_OFFSET_Y + (h - iy)/2,
-                        wxIMAGELIST_DRAW_TRANSPARENT
-                       );
+            wxDrawImageBitmap
+            (
+                this, *smallImages, image,
+                dc,
+                xAligned + wLabel - ix - HEADER_IMAGE_MARGIN_IN_REPORT_MODE,
+                HEADER_OFFSET_Y + (h - iy)/2
+            );
         }
 
         dc.DrawText( item.GetText(),
@@ -1576,8 +1577,8 @@ void wxListMainWindow::Init()
     m_headerWidth =
     m_lineHeight = 0;
 
-    m_small_image_list = NULL;
-    m_normal_image_list = NULL;
+    m_small_images = NULL;
+    m_normal_images = NULL;
 
     m_small_spacing = 30;
     m_normal_spacing = 40;
@@ -1735,10 +1736,10 @@ wxCoord wxListMainWindow::GetLineHeight() const
         wxCoord y;
         dc.GetTextExtent(wxT("H"), NULL, &y);
 
-        if ( m_small_image_list && m_small_image_list->GetImageCount() )
+        if ( m_small_images && m_small_images->GetImageCount() )
         {
             int iw = 0, ih = 0;
-            m_small_image_list->GetSize(0, iw, ih);
+            m_small_images->GetImageLogicalSize(this, 0, iw, ih);
             y = wxMax(y, ih);
         }
 
@@ -3286,41 +3287,25 @@ void wxListMainWindow::OnKillFocus( wxFocusEvent &WXUNUSED(event) )
 
 void wxListMainWindow::DrawImage( int index, wxDC *dc, int x, int y )
 {
-    if ( HasFlag(wxLC_ICON) && (m_normal_image_list))
-    {
-        m_normal_image_list->Draw( index, *dc, x, y, wxIMAGELIST_DRAW_TRANSPARENT );
-    }
-    else if ( HasFlag(wxLC_SMALL_ICON) && (m_small_image_list))
-    {
-        m_small_image_list->Draw( index, *dc, x, y, wxIMAGELIST_DRAW_TRANSPARENT );
-    }
-    else if ( HasFlag(wxLC_LIST) && (m_small_image_list))
+    if ( HasFlag(wxLC_ICON) && m_normal_images )
     {
-        m_small_image_list->Draw( index, *dc, x, y, wxIMAGELIST_DRAW_TRANSPARENT );
+        wxDrawImageBitmap(this, *m_normal_images, index, *dc, x, y);
     }
-    else if ( InReportView() && (m_small_image_list))
+    else if ( HasFlag(wxLC_SMALL_ICON | wxLC_LIST | wxLC_REPORT) && m_small_images )
     {
-        m_small_image_list->Draw( index, *dc, x, y, wxIMAGELIST_DRAW_TRANSPARENT );
+        wxDrawImageBitmap(this, *m_small_images, index, *dc, x, y);
     }
 }
 
 void wxListMainWindow::GetImageSize( int index, int &width, int &height ) const
 {
-    if ( HasFlag(wxLC_ICON) && m_normal_image_list )
-    {
-        m_normal_image_list->GetSize( index, width, height );
-    }
-    else if ( HasFlag(wxLC_SMALL_ICON) && m_small_image_list )
+    if ( HasFlag(wxLC_ICON) && m_normal_images )
     {
-        m_small_image_list->GetSize( index, width, height );
+        m_normal_images->GetImageLogicalSize(this, index, width, height);
     }
-    else if ( HasFlag(wxLC_LIST) && m_small_image_list )
+    else if ( HasFlag(wxLC_SMALL_ICON | wxLC_LIST | wxLC_REPORT) && m_small_images )
     {
-        m_small_image_list->GetSize( index, width, height );
-    }
-    else if ( InReportView() && m_small_image_list )
-    {
-        m_small_image_list->GetSize( index, width, height );
+        m_small_images->GetImageLogicalSize(this, index, width, height);
     }
     else
     {
@@ -3329,28 +3314,29 @@ void wxListMainWindow::GetImageSize( int index, int &width, int &height ) const
     }
 }
 
-void wxListMainWindow::SetImageList( wxImageList *imageList, int which )
+
+void wxListMainWindow::SetImages( wxWithImages *images, const int which )
 {
     m_dirty = true;
 
     // calc the spacing from the icon size
     int width = 0;
 
-    if ((imageList) && (imageList->GetImageCount()) )
+    if ((images) && (images->HasImages()) )
     {
         int height;
-        imageList->GetSize(0, width, height);
+        images->GetImageLogicalSize(this, 0, width, height);
     }
 
     if (which == wxIMAGE_LIST_NORMAL)
     {
-        m_normal_image_list = imageList;
+        m_normal_images = images;
         m_normal_spacing = width + 8;
     }
 
     if (which == wxIMAGE_LIST_SMALL)
     {
-        m_small_image_list = imageList;
+        m_small_images = images;
         m_small_spacing = width + 14;
         m_lineHeight = 0;  // ensure that the line height will be recalc'd
     }
@@ -3387,10 +3373,10 @@ wxListMainWindow::ComputeMinHeaderWidth(const wxListHeaderData* column) const
     const int image = column->GetImage();
     if ( image != -1 )
     {
-        if ( m_small_image_list )
+        if ( m_small_images )
         {
             int ix = 0, iy = 0;
-            m_small_image_list->GetSize(image, ix, iy);
+            m_small_images->GetImageLogicalSize(this, image, ix, iy);
             width += ix + HEADER_IMAGE_MARGIN_IN_REPORT_MODE;
         }
     }
@@ -4013,9 +3999,9 @@ void wxListMainWindow::RecalculatePositions()
     const size_t count = GetItemCount();
 
     int iconSpacing;
-    if ( HasFlag(wxLC_ICON) && m_normal_image_list )
+    if ( HasFlag(wxLC_ICON) && m_normal_images )
         iconSpacing = m_normal_spacing;
-    else if ( HasFlag(wxLC_SMALL_ICON) && m_small_image_list )
+    else if ( HasFlag(wxLC_SMALL_ICON) && m_small_images )
         iconSpacing = m_small_spacing;
     else
         iconSpacing = 0;
@@ -4610,10 +4596,10 @@ void wxListMainWindow::InsertItem( wxListItem &item )
     {
         // Reset the buffered height if it's not big enough for the new image.
         int image = item.GetImage();
-        if ( m_small_image_list && image != -1 && InReportView() )
+        if ( m_small_images && image != -1 && InReportView() )
         {
             int imageWidth, imageHeight;
-            m_small_image_list->GetSize(image, imageWidth, imageHeight);
+            m_small_images->GetImageLogicalSize(this, image, imageWidth, imageHeight);
 
             if ( imageHeight > m_lineHeight )
                 m_lineHeight = 0;
@@ -5440,7 +5426,7 @@ long wxGenericListCtrl::GetNextItem( long item, int geom, int state ) const
 
 void wxGenericListCtrl::DoUpdateImages(int which )
 {
-    m_mainWin->SetImageList( GetUpdatedImageList(which), which );
+    m_mainWin->SetImages( GetImages(which), which );
 }
 
 bool wxGenericListCtrl::Arrange( int WXUNUSED(flag) )

src/generic/treectlg.cpp

@@ -38,6 +38,8 @@
 
 #include "wx/renderer.h"
 
+#include "wx/generic/private/drawbitmap.h"
+
 #ifdef __WXMAC__
     #include "wx/osx/private.h"
 #endif
@@ -2648,24 +2650,23 @@ void wxGenericTreeCtrl::PaintItem(wxGenericTreeItem *item, wxDC& dc)
     if ( state != wxTREE_ITEMSTATE_NONE )
     {
         wxDCClipper clip(dc, item->GetX(), item->GetY(), state_w, total_h);
-        dc.DrawBitmap( m_imagesState.GetImageBitmapFor(this, state),
-                                item->GetX(),
-                                item->GetY() +
-                                    (total_h > state_h ? (total_h-state_h)/2
-                                                       : 0),
-                                true /* use mask */ );
+
+        wxDrawImageBitmap(this, m_imagesState, state,
+                          dc,
+                          item->GetX(),
+                          item->GetY() +
+                          total_h > state_h ? (total_h-state_h)/2 : 0);
     }
 
     if ( image != NO_IMAGE )
     {
         wxDCClipper clip(dc, item->GetX() + state_w, item->GetY(),
                              image_w, total_h);
-        dc.DrawBitmap( GetImageBitmapFor(this, image),
-                                 item->GetX() + state_w,
-                                 item->GetY() +
-                                    (total_h > image_h ? (total_h-image_h)/2
-                                                       : 0),
-                                 true /* use mask */ );
+        wxDrawImageBitmap(this, image,
+                          dc,
+                          item->GetX() + state_w,
+                          item->GetY() +
+                          total_h > image_h ? (total_h-image_h)/2 : 0);
     }
 
     dc.SetBackgroundMode(wxBRUSHSTYLE_TRANSPARENT);
@@ -2832,16 +2833,13 @@ wxGenericTreeCtrl::PaintLevel(wxGenericTreeItem *item,
                 if ( item->IsSelected() )
                     image += wxTreeItemIcon_Selected - wxTreeItemIcon_Normal;
 
-                const wxBitmap& bmp = m_imagesButtons.GetImageBitmapFor(this, image);
-
-                // we need logical coordinates for wxDC.
-                int image_h = FromPhys(bmp.GetHeight()),
-                    image_w = FromPhys(bmp.GetWidth());
+                int image_w, image_h;
+                m_imagesButtons.GetImageLogicalSize(this, image, image_w, image_h);
                 int xx = x - image_w/2;
                 int yy = y_mid - image_h/2;
 
                 wxDCClipper clip(dc, xx, yy, image_w, image_h);
-                dc.DrawBitmap( bmp, xx, yy, true /* use mask */ );
+                wxDrawImageBitmap(this, m_imagesButtons, image, dc, xx, yy);
             }
             else // no custom buttons
             {