From 53a1995e4082cd4cf2cb6762fd1fa7f02ffdb6e5 Mon Sep 17 00:00:00 2001
From: Selva Nair <selva.nair@gmail.com>
Date: Sat, 2 Jan 2021 15:00:15 -0500
Subject: [PATCH] Apply transparency mask to the connecting-state checkmark
 image

Use the image in the connecting state icon with background
color replaced by that of the menu for use as the checkmark.

MSDN docs on SetMenuItemBitmaps is unclear about the use of
color bitmaps for checkmarks, but this appears to display well.
(Tested on Windows 10 only).

The bitmap is recreated everytime the popup menus are made
although its sufficient to recreate it when system colours
change.

Signed-off-by: Selva Nair <selva.nair@gmail.com>
---
 tray.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 64 insertions(+), 10 deletions(-)

diff --git a/tray.c b/tray.c
index 59e51a6..4ee1fec 100644
--- a/tray.c
+++ b/tray.c
@@ -55,21 +55,75 @@ extern options_t o;
                                  || (o.config_menu_view == CONFIG_VIEW_NESTED))
 
 
-/* Create menu check bitmaps */
 static void
-CreateBitmaps()
+DeleteMenuBitmaps(void)
 {
-    if (hbmpConnecting)
-        return;
+    if (hbmpConnecting) {
+        DeleteObject(hbmpConnecting);
+        hbmpConnecting = NULL;
+    }
+}
+
+/* Create bitmaps for menu items. Currently only the connecting checkmark.
+ *
+ * Make a color bitmap from the connecting icon for use as a checkmark
+ * for indicating the connecting state. We do this by replacing
+ * the icon colour bitmap pixels in the background region with the menu
+ * color (COLOR_MENU)
+ */
+static void
+CreateMenuBitmaps(void)
+{
+
+    DeleteMenuBitmaps();
+
     int cx = GetSystemMetrics(SM_CXMENUCHECK);
     int cy = GetSystemMetrics(SM_CYMENUCHECK);
-    if (!hbmpConnecting)
+    HICON icon = LoadLocalizedIconEx(ID_ICO_CONNECTING, cx, cy);
+    ICONINFO iconinfo;
+
+    if (!icon || !GetIconInfo(icon, &iconinfo))
     {
-        HICON icon = LoadLocalizedIconEx(ID_ICO_CONNECTING, cx, cy);
-        ICONINFO iconinfo;
-        GetIconInfo(icon, &iconinfo);
-        hbmpConnecting = iconinfo.hbmColor;
+        MsgToEventLog(EVENTLOG_ERROR_TYPE, L"Error loading ID_ICO_CONNECTING.");
+        return;
     }
+
+    /* Create two DCs for drawing/accessing the images in memory */
+    HDC maskDC = CreateCompatibleDC(NULL), imgDC = CreateCompatibleDC(NULL);
+    if (!maskDC || !imgDC)
+    {
+        DeleteObject(iconinfo.hbmMask);
+        DeleteObject(iconinfo.hbmColor);
+        if (maskDC) DeleteDC(maskDC);
+        if (imgDC) DeleteDC(imgDC);
+        MsgToEventLog(EVENTLOG_ERROR_TYPE, L"Error creating DCs for drawing");
+        return;
+    }
+
+    /* Load the image and mask bitmaps into the DCs saving the default one's */
+    HBITMAP def1 = (HBITMAP) SelectObject(imgDC, iconinfo.hbmColor);
+    HBITMAP def2 = (HBITMAP) SelectObject(maskDC, iconinfo.hbmMask);
+
+    /* White mask pixels mark the background region */
+    COLORREF ref = RGB(255, 255, 255);
+    COLORREF bg = GetSysColor(COLOR_MENU);
+
+    for (int x = 0; x < cx; x++) {
+        for (int y = 0; y < cy; y++) {
+            if (GetPixel(maskDC, x, y) == ref)
+                SetPixel(imgDC, x, y, bg);
+        }
+    }
+
+    /* Save the result and restore the default bitmaps back in the DC */
+    hbmpConnecting = (HBITMAP) SelectObject(imgDC, def1);
+    SelectObject(maskDC, def2);
+
+    /* We don't need the mask bitmap -- free it */
+    DeleteObject(iconinfo.hbmMask);
+
+    DeleteDC(imgDC);
+    DeleteDC(maskDC);
 }
 
 /*
@@ -105,7 +159,7 @@ CreatePopupMenus()
 
     AllocateConnectionMenu();
 
-    CreateBitmaps();
+    CreateMenuBitmaps();
     MENUINFO minfo = {.cbSize = sizeof(MENUINFO)};
 
     for (int i = 0; i < o.num_configs; i++)