From 479d1226faaa937ef6820b14f36099ef3f575883 Mon Sep 17 00:00:00 2001
From: Jonas Kümmerlin <jonas@kuemmerlin.eu>
Date: Sat, 18 Apr 2020 17:34:55 +0200
Subject: implement background color

reduce flickering by keeping pixels if we know the background didn't change

panel text is now gone, it would require us to redraw every transparent
widget on top, which is a bad tradeoff since that panel text isn't very
useful anyway.
---
 alf/alfpanel.cpp | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

(limited to 'alf/alfpanel.cpp')

diff --git a/alf/alfpanel.cpp b/alf/alfpanel.cpp
index 9496e43..2f39ef1 100644
--- a/alf/alfpanel.cpp
+++ b/alf/alfpanel.cpp
@@ -4,6 +4,7 @@ TCHAR *_alf_panelClass = NULL;
 
 typedef struct {
     ALFLayout layout;
+    ALFColor bgcolor;
     HFONT font;
 } ALFPanelPriv;
 
@@ -11,6 +12,7 @@ static void
 ALF_Panel_IntializePriv(ALFPanelPriv *priv)
 {
     ALF_Layout_Init(&priv->layout);
+    priv->bgcolor = ALF_COLOR_TRANSPARENT;
 }
 
 static void
@@ -22,29 +24,11 @@ ALF_Panel_ClearPriv(ALFPanelPriv *priv)
 static void
 ALF_Panel_Paint(ALFPanelPriv *priv, HWND hwnd, HDC dc, RECT *r)
 {
-    (void)priv;
-    ALF_Compat_DrawThemeParentBackground(hwnd, dc, r);
-
-    int textlen = GetWindowTextLength(hwnd);
-    if (textlen < 1)
-        return;
-
-    TCHAR *textbuf = ALF_New(TCHAR, (SIZE_T)textlen + 1);
-    GetWindowText(hwnd, textbuf, textlen+1);
-
-    HFONT oldFont = SelectFont(dc, priv->font);
-
-    SetTextColor(dc, GetSysColor(COLOR_BTNTEXT));
-    SetBkMode(dc, TRANSPARENT);
-
-    RECT rc;
-    GetClientRect(hwnd, &rc);
-
-    DrawText(dc, textbuf, -1, &rc, DT_SINGLELINE | DT_EXPANDTABS | DT_HIDEPREFIX | DT_CENTER | DT_VCENTER);
-
-    ALF_Free(textbuf);
-
-    SelectFont(dc, oldFont);
+    if (priv->bgcolor == ALF_COLOR_TRANSPARENT) {
+        ALF_Compat_DrawThemeParentBackground(hwnd, dc, r);
+    } else {
+        ALF_FillRect(dc, r, priv->bgcolor);
+    }
 }
 
 static LRESULT WINAPI
@@ -78,6 +62,18 @@ ALF__PanelWindowProc(HWND window, UINT msg, WPARAM wparam, LPARAM lparam)
         // fallthrough to layout, will propagate font to children
     }
 
+    if (msg == ALF_WM_GETBGCOLOR) {
+        return (LRESULT)priv->bgcolor;
+    }
+
+    if (msg == ALF_WM_SETBGCOLOR) {
+        priv->bgcolor = (ALFColor)wparam;
+
+        InvalidateRect(window, NULL, TRUE);
+
+        // fallthrough to layout, will propagate color to children
+    }
+
     if (msg == WM_GETFONT) {
         return (LRESULT)priv->font;
     }
@@ -160,7 +156,7 @@ ALF_AddPanel(HWND parent, WORD id, int x, int y)
 {
     HWND hwndPanel = ALF_CreatePanelWindow(parent, id);
 
-    ALF_AddWidget(parent, x, y, hwndPanel, 0, 0, ALF_LAYOUT_SIZE_QUERY | ALF_LAYOUT_INHERITFONT);
+    ALF_AddWidget(parent, x, y, hwndPanel, 0, 0, ALF_LAYOUT_SIZE_QUERY | ALF_LAYOUT_INHERITFONT | ALF_LAYOUT_INHERITBGCOLOR);
 
     return hwndPanel;
 }
-- 
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