From 416fe35c67352dd23ad698d8f732545caee3d82d Mon Sep 17 00:00:00 2001
From: Jonas Kümmerlin <jonas@kuemmerlin.eu>
Date: Fri, 28 Dec 2018 21:40:36 +0100
Subject: add per-monitor dpi support

---
 alf/alf.cpp | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

(limited to 'alf/alf.cpp')

diff --git a/alf/alf.cpp b/alf/alf.cpp
index 2ec33ca..9b2f60f 100644
--- a/alf/alf.cpp
+++ b/alf/alf.cpp
@@ -1,5 +1,9 @@
 #include "alfpriv.h"
 
+#ifndef WM_DPICHANGED
+#define WM_DPICHANGED       0x02E0
+#endif
+
 /* ALF App and Window */
 
 static void
@@ -39,31 +43,25 @@ ALF_UpdateFontForWidget(ALFWindowPriv *priv, ALFWidgetPriv *widget)
 {
     if (widget->hwnd && (widget->flags & ALF_MESSAGEFONT) == ALF_MESSAGEFONT) {
         SendMessage(widget->hwnd, WM_SETFONT, (WPARAM)priv->fonts.hMessageFont, (LPARAM)NULL);
+
+        // XXX: Invalidating should IMHO be the decision of the control, but at
+        // least the commctl32 V5 static control doesn't do it.
+        InvalidateRect(widget->hwnd, NULL, TRUE);
     }
 }
 
 void
 ALF_UpdateFonts(HWND win)
 {
-    // TODO per-monitor DPI aware: GetDpiForWindow, SystemParametersInfoForDpi etc.
     ALFWindowPriv *priv = (ALFWindowPriv*)GetWindowLongPtr(win, 0);
 
-    priv->fonts.dpi = 0;
-    HDC hdcScreen = GetDC(NULL);
-    if (hdcScreen) {
-        priv->fonts.dpi = GetDeviceCaps(hdcScreen, LOGPIXELSY);
-        ReleaseDC(NULL, hdcScreen);
-    }
-
-    if (!priv->fonts.dpi) {
-        priv->fonts.dpi = 96; // FIXME! fallback to default DPI
-    }
+    priv->fonts.dpi = priv->app->compatFn->GetDpiForWindow(win);
 
     NONCLIENTMETRICS ncm;
     ZeroMemory(&ncm, sizeof(ncm));
     ncm.cbSize = sizeof(ncm);
 
-    if (SystemParametersInfoW(SPI_GETNONCLIENTMETRICS, ncm.cbSize, &ncm, 0)) {
+    if (priv->app->compatFn->SystemParametersInfoForDpi(SPI_GETNONCLIENTMETRICS, ncm.cbSize, &ncm, 0, priv->fonts.dpi)) {
         priv->fonts.lfMessageFont = ncm.lfMessageFont;
     } else {
         // FIXME! fallback to default font, 8pt MS Shell Dlg
@@ -375,11 +373,12 @@ ALF_DefWindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
         tmp.right = priv->layout.totalMinWidth;
         tmp.bottom = priv->layout.totalMinHeight;
 
-        // TODO ..ForDpi
-        if (AdjustWindowRectEx(&tmp,
+        if (priv->app->compatFn->AdjustWindowRectExForDpi(
+                               &tmp,
                                GetWindowLong(hwnd, GWL_STYLE),
                                GetMenu(hwnd) != NULL,
-                               GetWindowLong(hwnd, GWL_EXSTYLE))) {
+                               GetWindowLong(hwnd, GWL_EXSTYLE),
+                               priv->fonts.dpi)) {
             MINMAXINFO *i = (MINMAXINFO *)lparam;
             i->ptMinTrackSize.x = tmp.right - tmp.left;
             i->ptMinTrackSize.y = tmp.bottom - tmp.top;
@@ -417,6 +416,13 @@ ALF_DefWindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
         ALF_DestroyWindowPriv(priv);
     }
 
+    if (msg == WM_DPICHANGED) {
+        ALF_UpdateFonts(hwnd);
+        ALF_RecalculateLayout(hwnd);
+        RECT *r = (RECT*)lparam;
+        SetWindowPos(hwnd, NULL, r->left, r->top, r->right-r->left, r->bottom-r->top, SWP_NOACTIVATE|SWP_NOZORDER);
+    }
+
     if (msg == DM_GETDEFID) {
         if (priv->defid == (WORD)-1) {
             return 0;
-- 
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