Implement themed rendering for ListView and Header in ThemeRenderer

- Migrated custom drawing logic from FileList to ThemeRenderer.
- Introduced IListViewDataProvider interface to decouple ThemeRenderer from FileList.
- Implemented themed rendering for ListView Header (WC_HEADER) in dark mode.
- Handled NM_CUSTOMDRAW for ListView items in parent window subclass to support themes.
- Improved TreeView support by applying DarkMode_Explorer theme.
- Fixed header rendering using BeginPaint/EndPaint in WM_PAINT handler.
- Cleaned up FileList by removing redundant custom draw logic.

Co-authored-by: funap <31555185+funap@users.noreply.github.com>

Author: google-labs-jules[bot]

src/Explorer/FileList.cpp

@@ -89,11 +89,21 @@ FileList::~FileList()
 {
 }
 
+bool FileList::IsFileOpen(size_t index) const
+{
+    if (index >= _uMaxFolders) {
+        std::wstring strFilePath = _pSettings->GetCurrentDir() + _vFileList[index].Name();
+        return ::IsFileOpen(strFilePath) == TRUE;
+    }
+    return false;
+}
+
 void FileList::init(HINSTANCE hInst, HWND hParent, HWND hParentList)
 {
     /* this is the list element */
     Window::init(hInst, hParent);
     _hSelf = hParentList;
+    ::SetWindowLongPtr(_hSelf, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(static_cast<IListViewDataProvider*>(this)));
 
     /* create semaphore for thead */
     _hSemaphore = ::CreateSemaphore(nullptr, 1, 1, nullptr);
@@ -534,38 +544,8 @@ BOOL FileList::notify(WPARAM wParam, LPARAM lParam)
             UpdateSelItems();
             break;
         case NM_CUSTOMDRAW: {
-            LPNMLVCUSTOMDRAW lpCD = (LPNMLVCUSTOMDRAW)lParam;
-            switch (lpCD->nmcd.dwDrawStage) {
-            case CDDS_PREPAINT:
-                ::SetWindowLongPtr(_hParent, DWLP_MSGRESULT, CDRF_NOTIFYITEMDRAW);
-                return TRUE;
-            case CDDS_ITEMPREPAINT: {
-                auto index = static_cast<INT>(lpCD->nmcd.dwItemSpec);
-                if (index >= static_cast<INT>(_uMaxFolders)) {
-                    std::wstring strFilePath = _pSettings->GetCurrentDir() + _vFileList[index].Name();
-                    if (IsFileOpen(strFilePath) == TRUE) {
-                        ::SelectObject(lpCD->nmcd.hdc, _pSettings->GetUnderlineFont());
-                        ::SetWindowLongPtr(_hParent, DWLP_MSGRESULT, CDRF_NEWFONT);
-                    }
-                }
-                if (_vFileList[index].IsParent()) {
-                    ::SetWindowLongPtr(_hParent, DWLP_MSGRESULT, CDRF_NOTIFYPOSTPAINT);
-                }
-                return TRUE;
-            }
-            case CDDS_ITEMPOSTPAINT: {
-                auto index = static_cast<INT>(lpCD->nmcd.dwItemSpec);
-                RECT rc {};
-                ListView_GetSubItemRect(_hSelf, index, lpCD->iSubItem, LVIR_ICON, &rc);
-                UINT state = ListView_GetItemState(_hSelf, index, LVIS_SELECTED);
-                bool isSelected = ((state & LVIS_SELECTED) ? (::GetFocus() == _hSelf) : ((state & LVIS_DROPHILITED) == LVIS_DROPHILITED));
-                ImageList_Draw(_hImlParent, ICON_PARENT, lpCD->nmcd.hdc, rc.left, rc.top, ILD_NORMAL | (isSelected ? ILD_SELECTED : 0));
-                return TRUE;
-            }
-            default:
-                return FALSE;
-            }
-            break;
+            // Handled by ThemeRenderer
+            return FALSE;
         }
         default:
             break;

src/Explorer/FileList.h

@@ -46,9 +46,10 @@ static const WORD DotPattern[] =
 };
 
 #include "FileSystemService.h"
+#include "ThemeRenderer.h"
 
 
-class FileList : public Window, public CIDropTarget
+class FileList : public Window, public CIDropTarget, public IListViewDataProvider
 {
 public:
     FileList() = delete;
@@ -58,6 +59,17 @@ class FileList : public Window, public CIDropTarget
     void init(HINSTANCE hInst, HWND hParent, HWND hParentList);
     void initProp(Settings* prop);
 
+    // IListViewDataProvider
+    virtual size_t GetMaxFolders() const override { return _uMaxFolders; }
+    virtual std::wstring GetItemName(size_t index) const override { return _vFileList[index].Name(); }
+    virtual bool IsItemParent(size_t index) const override { return _vFileList[index].IsParent(); }
+    virtual bool IsFileOpen(size_t index) const override;
+    virtual HFONT GetUnderlineFont() const override { return _pSettings->GetUnderlineFont(); }
+    virtual HIMAGELIST GetParentImageList() const override { return _hImlParent; }
+
+    bool IsItemHidden(size_t index) const { return _vFileList[index].IsHidden(); }
+    Settings* GetSettings() const { return _pSettings; }
+
     void viewPath(const std::wstring& currentDir, BOOL redraw = FALSE);
 
     BOOL notify(WPARAM wParam, LPARAM lParam);

src/Explorer/ThemeRenderer.cpp

@@ -26,12 +26,15 @@
 #include <uxtheme.h>
 #include <Vsstyle.h>
 #include <Vssym32.h>
+#include "FileList.h"
 
 namespace {
 constexpr UINT_PTR WINDOW_SUBCLASS_ID   = 0;
 constexpr UINT_PTR REBAR_SUBCLASS_ID    = 1;
 constexpr UINT_PTR BUTTON_SUBCLASS_ID   = 2;
 constexpr UINT_PTR EDIT_SUBCLASS_ID     = 3;
+constexpr UINT_PTR LISTVIEW_SUBCLASS_ID = 4;
+constexpr UINT_PTR HEADER_SUBCLASS_ID   = 5;
 
 auto GetClassName(HWND hwnd) -> std::wstring
 {
@@ -135,6 +138,16 @@ void ThemeRenderer::Register(HWND hwnd)
         else if (className == WC_EDIT) {
             ::SetWindowSubclass(childWindow, DefaultSubclassProc, EDIT_SUBCLASS_ID, reinterpret_cast<DWORD_PTR>(self));
         }
+        else if (className == WC_LISTVIEW) {
+            ::SetWindowSubclass(childWindow, DefaultSubclassProc, LISTVIEW_SUBCLASS_ID, reinterpret_cast<DWORD_PTR>(self));
+            HWND hHeader = ListView_GetHeader(childWindow);
+            if (hHeader) {
+                ::SetWindowSubclass(hHeader, DefaultSubclassProc, HEADER_SUBCLASS_ID, reinterpret_cast<DWORD_PTR>(self));
+            }
+        }
+        else if (className == WC_TREEVIEW) {
+            ::SetWindowTheme(childWindow, self->m_isDarkMode ? L"DarkMode_Explorer" : L"Explorer", nullptr);
+        }
         return TRUE;
     }, reinterpret_cast<LPARAM>(this));
 
@@ -164,6 +177,16 @@ void ThemeRenderer::ApplyTheme(HWND hwnd)
             ListView_SetTextColor(childWindow, self->m_colors.secondary);
             ListView_SetTextBkColor(childWindow, CLR_NONE);
             ::SetWindowTheme(childWindow, self->m_isDarkMode ? L"DarkMode_Explorer" : L"Explorer", nullptr);
+
+            HWND hHeader = ListView_GetHeader(childWindow);
+            if (hHeader) {
+                ::SetWindowSubclass(hHeader, DefaultSubclassProc, HEADER_SUBCLASS_ID, reinterpret_cast<DWORD_PTR>(self));
+            }
+        }
+        else if (className == WC_TREEVIEW) {
+            TreeView_SetBkColor(childWindow, self->m_colors.secondary_bg);
+            TreeView_SetTextColor(childWindow, self->m_colors.secondary);
+            ::SetWindowTheme(childWindow, self->m_isDarkMode ? L"DarkMode_Explorer" : L"Explorer", nullptr);
         }
         return TRUE;
     }, reinterpret_cast<LPARAM>(this));
@@ -181,6 +204,10 @@ LRESULT CALLBACK ThemeRenderer::DefaultSubclassProc(HWND hWnd, UINT uMsg, WPARAM
         return self->ButtonProc(hWnd, uMsg, wParam, lParam);
     case EDIT_SUBCLASS_ID:
         return self->EditProc(hWnd, uMsg, wParam, lParam);
+    case LISTVIEW_SUBCLASS_ID:
+        return self->ListViewProc(hWnd, uMsg, wParam, lParam);
+    case HEADER_SUBCLASS_ID:
+        return self->HeaderProc(hWnd, uMsg, wParam, lParam);
     default:
         break;
     }
@@ -203,6 +230,54 @@ LRESULT ThemeRenderer::WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lP
         ::SetBkColor(hdc, m_colors.secondary_bg);
         return (LRESULT)(HBRUSH)m_brushes.secondary_bg;
     }
+    case WM_NOTIFY: {
+        LPNMHDR nmhdr = (LPNMHDR)lParam;
+        if (nmhdr->code == NM_CUSTOMDRAW) {
+            std::wstring className = GetClassName(nmhdr->hwndFrom);
+            if (className == WC_LISTVIEW) {
+                LPNMLVCUSTOMDRAW lpCD = (LPNMLVCUSTOMDRAW)lParam;
+                switch (lpCD->nmcd.dwDrawStage) {
+                case CDDS_PREPAINT:
+                    return CDRF_NOTIFYITEMDRAW;
+                case CDDS_ITEMPREPAINT: {
+                    auto index = static_cast<INT>(lpCD->nmcd.dwItemSpec);
+                    IListViewDataProvider* pDataProvider = reinterpret_cast<IListViewDataProvider*>(::GetWindowLongPtr(nmhdr->hwndFrom, GWLP_USERDATA));
+
+                    if (m_isDarkMode) {
+                        lpCD->clrText = m_colors.secondary;
+                        lpCD->clrTextBk = m_colors.secondary_bg;
+
+                        if (lpCD->nmcd.uItemState & CDIS_SELECTED) {
+                            lpCD->clrText = m_colors.primary;
+                            lpCD->clrTextBk = m_colors.primary_bg;
+                        }
+                    }
+
+                    if (pDataProvider) {
+                        if (pDataProvider->IsFileOpen(index)) {
+                            ::SelectObject(lpCD->nmcd.hdc, pDataProvider->GetUnderlineFont());
+                        }
+                    }
+
+                    return CDRF_NEWFONT | CDRF_NOTIFYPOSTPAINT;
+                }
+                case CDDS_ITEMPOSTPAINT: {
+                    auto index = static_cast<INT>(lpCD->nmcd.dwItemSpec);
+                    IListViewDataProvider* pDataProvider = reinterpret_cast<IListViewDataProvider*>(::GetWindowLongPtr(nmhdr->hwndFrom, GWLP_USERDATA));
+                    if (pDataProvider && pDataProvider->IsItemParent(index)) {
+                        RECT rc {};
+                        ListView_GetSubItemRect(nmhdr->hwndFrom, index, lpCD->iSubItem, LVIR_ICON, &rc);
+                        UINT state = ListView_GetItemState(nmhdr->hwndFrom, index, LVIS_SELECTED | LVIS_DROPHILITED);
+                        bool isSelected = ((state & LVIS_SELECTED) ? (::GetFocus() == nmhdr->hwndFrom) : ((state & LVIS_DROPHILITED) == LVIS_DROPHILITED));
+                        ImageList_Draw(pDataProvider->GetParentImageList(), ICON_PARENT, lpCD->nmcd.hdc, rc.left, rc.top, ILD_NORMAL | (isSelected ? ILD_SELECTED : 0));
+                    }
+                    return CDRF_DODEFAULT;
+                }
+                }
+            }
+        }
+        break;
+    }
     case WM_NCDESTROY:
         ::RemoveWindowSubclass(hWnd, DefaultSubclassProc, REBAR_SUBCLASS_ID);
         m_windows.erase(hWnd);
@@ -266,7 +341,88 @@ LRESULT ThemeRenderer::EditProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lPar
     }
     case WM_NCDESTROY:
         ::RemoveWindowSubclass(hWnd, DefaultSubclassProc, EDIT_SUBCLASS_ID);
-        m_windows.erase(hWnd);
+        break;
+    }
+    return ::DefSubclassProc(hWnd, uMsg, wParam, lParam);
+}
+
+LRESULT ThemeRenderer::ListViewProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+    switch (uMsg) {
+    case WM_NCDESTROY:
+        ::RemoveWindowSubclass(hWnd, DefaultSubclassProc, LISTVIEW_SUBCLASS_ID);
+        break;
+    }
+    return ::DefSubclassProc(hWnd, uMsg, wParam, lParam);
+}
+
+LRESULT ThemeRenderer::HeaderProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+    switch (uMsg) {
+    case WM_PAINT: {
+        if (!m_isDarkMode) break;
+        PAINTSTRUCT ps;
+        HDC hdc = BeginPaint(hWnd, &ps);
+
+        RECT rcHeader;
+        GetClientRect(hWnd, &rcHeader);
+
+        // Fill background
+        FillRect(hdc, &rcHeader, m_brushes.secondary_bg);
+
+        int count = Header_GetItemCount(hWnd);
+        for (int i = 0; i < count; i++) {
+            RECT rcItem;
+            Header_GetItemRect(hWnd, i, &rcItem);
+
+            // Draw text
+            WCHAR text[MAX_PATH];
+            HDITEM hdi = { .mask = HDI_TEXT | HDI_FORMAT, .pszText = text, .cchTextMax = MAX_PATH };
+            Header_GetItem(hWnd, i, &hdi);
+
+            SetTextColor(hdc, m_colors.secondary);
+            SetBkMode(hdc, TRANSPARENT);
+
+            RECT rcText = rcItem;
+            rcText.left += 6;
+            DrawText(hdc, text, -1, &rcText, DT_LEFT | DT_VCENTER | DT_SINGLELINE | DT_END_ELLIPSIS);
+
+            // Draw sort arrow
+            if (hdi.fmt & (HDF_SORTUP | HDF_SORTDOWN)) {
+                HPEN hPen = CreatePen(PS_SOLID, 1, m_colors.secondary);
+                HPEN hOldPen = (HPEN)SelectObject(hdc, hPen);
+
+                int x = rcItem.right - 15;
+                int y = rcItem.top + (rcItem.bottom - rcItem.top) / 2;
+
+                if (hdi.fmt & HDF_SORTUP) {
+                    MoveToEx(hdc, x, y + 2, nullptr);
+                    LineTo(hdc, x + 4, y - 2);
+                    LineTo(hdc, x + 8, y + 2);
+                    LineTo(hdc, x, y + 2);
+                } else {
+                    MoveToEx(hdc, x, y - 2, nullptr);
+                    LineTo(hdc, x + 4, y + 2);
+                    LineTo(hdc, x + 8, y - 2);
+                    LineTo(hdc, x, y - 2);
+                }
+
+                SelectObject(hdc, hOldPen);
+                DeleteObject(hPen);
+            }
+
+            // Draw separator
+            if (i < count - 1) {
+                RECT rcSep = { rcItem.right - 1, rcItem.top + 4, rcItem.right, rcItem.bottom - 4 };
+                FillRect(hdc, &rcSep, m_brushes.border);
+            }
+        }
+
+        EndPaint(hWnd, &ps);
+        return 0;
+    }
+    case WM_NCDESTROY:
+        ::RemoveWindowSubclass(hWnd, DefaultSubclassProc, HEADER_SUBCLASS_ID);
         break;
     }
     return ::DefSubclassProc(hWnd, uMsg, wParam, lParam);

src/Explorer/ThemeRenderer.h

@@ -28,6 +28,7 @@
 #include <memory>
 #include <set>
 #include <stdexcept>
+#include <string>
 
 #include "Graphics.h"
 
@@ -56,6 +57,17 @@ struct Brushes
     Brush primary_border; // for primary element borders
 };
 
+class IListViewDataProvider {
+public:
+    virtual ~IListViewDataProvider() = default;
+    virtual size_t GetMaxFolders() const = 0;
+    virtual std::wstring GetItemName(size_t index) const = 0;
+    virtual bool IsItemParent(size_t index) const = 0;
+    virtual bool IsFileOpen(size_t index) const = 0;
+    virtual HFONT GetUnderlineFont() const = 0;
+    virtual HIMAGELIST GetParentImageList() const = 0;
+};
+
 class ThemeRenderer
 {
 private:
@@ -101,6 +113,8 @@ class ThemeRenderer
     LRESULT RebarProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
     LRESULT ButtonProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
     LRESULT EditProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
+    LRESULT ListViewProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
+    LRESULT HeaderProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
 
     BOOL    m_isDarkMode;
     ThemeColors  m_colors;