From b28efb6896dd6b0ff94fa1e7a3a8a59a0029d595 Mon Sep 17 00:00:00 2001
From: aubymori <aubyomori@gmail.com>
Date: Tue, 17 Sep 2024 15:31:58 -0500
Subject: [PATCH] Custom Desktop Watermark 1.0.0

---
 mods/custom-desktop-watermark.wh.cpp | 199 +++++++++++++++++++++++++++
 1 file changed, 199 insertions(+)
 create mode 100644 mods/custom-desktop-watermark.wh.cpp

diff --git a/mods/custom-desktop-watermark.wh.cpp b/mods/custom-desktop-watermark.wh.cpp
new file mode 100644
index 000000000..0ea1152a5
--- /dev/null
+++ b/mods/custom-desktop-watermark.wh.cpp
@@ -0,0 +1,199 @@
+// ==WindhawkMod==
+// @id              custom-desktop-watermark
+// @name            Custom Desktop Watermark
+// @description     Lets you set your own desktop watermark text
+// @version         1.0.0
+// @author          aubymori
+// @github          https://github.com/aubymori
+// @include         explorer.exe
+// @compilerOptions -lgdi32 -DWINVER=0x0A00
+// ==/WindhawkMod==
+
+// ==WindhawkModReadme==
+/*
+# Custom Desktop Watermark
+This mod allows you to completely customize the desktop watermark,
+putting in your own lines of text.
+
+## Examples
+
+**Windows 7 (not genuine)**:
+![Windows 7 (not genuine)](https://raw.githubusercontent.com/aubymori/images/main/custom-desktop-watermark-win7.png)
+
+**Windows XP Professional x64 Edition**:
+![Windows XP Professional x64 Edition](https://raw.githubusercontent.com/aubymori/images/main/custom-desktop-watermark-winxp.png)
+*/
+// ==/WindhawkModReadme==
+
+// ==WindhawkModSettings==
+/*
+- lines:
+  - - text: ""
+      $name: Text
+    - title: false
+      $name: Use caption font
+      $description: Use caption font instead of message font when classic fonts are enabled.
+  $name: Text lines
+- classic: false
+  $name: Use classic fonts
+  $description: Use caption/message font instead of just caption font.
+*/
+// ==/WindhawkModSettings==
+
+#include <windhawk_utils.h>
+#include <windows.h>
+#include <vector>
+
+#define RECTWIDTH(rc)   ((rc).right - (rc).left)
+#define RECTHEIGHT(rc)  ((rc).bottom - (rc).top)
+
+WINUSERAPI BOOL WINAPI SystemParametersInfoForDpi(UINT uiAction, UINT uiParam, PVOID pvParam, UINT fWinIni, UINT dpi);
+
+struct WatermarkLine
+{
+    std::wstring text;
+    bool title;
+};
+
+std::vector<WatermarkLine> g_lines;
+bool g_bClassic = false;
+
+bool (*CDesktopWatermark_s_WantWatermark_orig)(void);
+bool CDesktopWatermark_s_WantWatermark_hook(void)
+{
+    return true;
+}
+
+int PaintLine(
+    HDC            hDC,
+    LPCRECT        lprc,
+    LPCWSTR        lpszText,
+    HFONT          hFont,
+    int            offset
+)
+{
+    HFONT hfOld = (HFONT)SelectObject(hDC, hFont);
+        
+    RECT rcText = { 0 };
+    int newOffset = DrawTextW(
+        hDC, lpszText, -1,
+        &rcText, DT_CALCRECT | DT_SINGLELINE
+    );
+
+    RECT rcPaint = { 0 };
+    rcPaint.left = lprc->right - RECTWIDTH(rcText);
+    rcPaint.top = lprc->bottom - RECTHEIGHT(rcText);
+    rcPaint.right = lprc->right;
+    rcPaint.bottom = lprc->bottom;
+
+    int padding = MulDiv(5, GetDeviceCaps(hDC, LOGPIXELSX), 96);
+    OffsetRect(&rcPaint, -padding, -offset);
+
+    DrawTextW(hDC, lpszText, -1, &rcPaint, DT_SINGLELINE);
+
+    SelectObject(hDC, hfOld);
+    return newOffset;    
+}
+
+void (*CDesktopWatermark_s_DesktopBuildPaint_orig)(HDC, LPCRECT, HFONT);
+void CDesktopWatermark_s_DesktopBuildPaint_hook(
+    HDC     hDC,
+    LPCRECT lprc,
+    HFONT   hFont
+)
+{
+    COLORREF cr = SetTextColor(hDC, RGB(255, 255, 255));
+    int offset = 0;
+
+    NONCLIENTMETRICSW ncm = { sizeof(ncm) };
+    int dpi = GetDeviceCaps(hDC, LOGPIXELSX);
+    SystemParametersInfoForDpi(
+        SPI_GETNONCLIENTMETRICS,
+        sizeof(ncm),
+        &ncm,
+        0,
+        dpi
+    );
+    HFONT hTitleFont = CreateFontIndirectW(&ncm.lfCaptionFont);
+    HFONT hMessageFont = CreateFontIndirectW(&ncm.lfMessageFont);
+    int padding = MulDiv(3, dpi, 96);
+    offset += MulDiv(g_bClassic ? 4 : 1, dpi, 96);
+
+    for (size_t i = g_lines.size(); i--;)
+    {
+        WatermarkLine line = g_lines.at(i);
+        bool bMessageFont = g_bClassic && !line.title;
+
+        offset += PaintLine(
+            hDC, lprc, line.text.c_str(),
+            bMessageFont ? hMessageFont : hTitleFont,
+            offset
+        ) + padding;
+    }
+
+    SetTextColor(hDC, cr);
+}
+
+const WindhawkUtils::SYMBOL_HOOK shell32DllHooks[] = {
+    {
+        {
+            L"public: static bool __cdecl CDesktopWatermark::s_WantWatermark(void)"
+        },
+        &CDesktopWatermark_s_WantWatermark_orig,
+        CDesktopWatermark_s_WantWatermark_hook,
+        false
+    },
+    {
+        {
+            L"private: static void __cdecl CDesktopWatermark::s_DesktopBuildPaint(struct HDC__ *,struct tagRECT const *,struct HFONT__ *)"
+        },
+        &CDesktopWatermark_s_DesktopBuildPaint_orig,
+        CDesktopWatermark_s_DesktopBuildPaint_hook,
+        false
+    }
+};
+
+void LoadSettings(void)
+{
+    g_lines.clear();
+    g_bClassic = Wh_GetIntSetting(L"classic");
+
+    for (int i = 0;; i++)
+    {
+        LPCWSTR lpszText = Wh_GetStringSetting(L"lines[%i].text", i);
+        if (!lpszText || !*lpszText)
+            break;
+        bool title = Wh_GetIntSetting(L"lines[%i].title", i);
+        WatermarkLine line = { lpszText, title };
+        g_lines.push_back(line);
+    }
+}
+
+BOOL Wh_ModInit(void)
+{
+    LoadSettings();
+
+    HMODULE hShell32 = LoadLibraryW(L"shell32.dll");
+    if (!hShell32)
+    {
+        Wh_Log(L"Failed to load shell32.dll");
+        return FALSE;
+    }
+
+    if (!WindhawkUtils::HookSymbols(
+        hShell32,
+        shell32DllHooks,
+        ARRAYSIZE(shell32DllHooks)
+    ))
+    {
+        Wh_Log(L"Failed to hook one or more symbol functions in shell32.dll");
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+void Wh_ModSettingsChanged(void)
+{
+    LoadSettings();
+}
\ No newline at end of file