From 2ddd9e55ff010d9c10ac87fdfca0cfc8d76592ff Mon Sep 17 00:00:00 2001
From: rupor-github <rupor0mail@gmail.com>
Date: Sat, 19 Dec 2015 10:02:26 -0500
Subject: [PATCH] Simple font scaling on WM_DPICHANGED

---
 src/winmain.c | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/src/winmain.c b/src/winmain.c
index 1f0bbdfc..0b82ffa8 100644
--- a/src/winmain.c
+++ b/src/winmain.c
@@ -17,6 +17,7 @@
 #include <getopt.h>
 #include <pwd.h>
 #include <shellapi.h>
+#include <math.h>
 
 #include <sys/cygwin.h>
 
@@ -64,6 +65,7 @@ static bool maxwidth = false;
 static bool maxheight = false;
 static bool store_taskbar_properties = false;
 static bool prevent_pinning = false;
+static int last_dpi = 0;
 
 static HBITMAP caretbm;
 
@@ -123,6 +125,7 @@ const int Process_Per_Monitor_DPI_Aware  = 2;
 const int MDT_Effective_DPI = 0;
 static HRESULT (WINAPI * pGetProcessDpiAwareness)(HANDLE hprocess, int * value) = 0;
 static HRESULT (WINAPI * pSetProcessDpiAwareness)(int value) = 0;
+static HRESULT (WINAPI * pGetDpiForMonitor)(HMONITOR hmonitor, int dpiType, UINT * dpiX, UINT * dpiY);
 
 static void
 load_shcore_funcs(void)
@@ -136,6 +139,8 @@ load_shcore_funcs(void)
       (void *)GetProcAddress(shc, "GetProcessDpiAwareness");
     pSetProcessDpiAwareness =
       (void *)GetProcAddress(shc, "SetProcessDpiAwareness");
+    pGetDpiForMonitor =
+      (void *)GetProcAddress(shc, "GetDpiForMonitor");
 #ifdef debug_dpi
       printf("SetProcessDpiAwareness %d GetProcessDpiAwareness %d\n", !!pSetProcessDpiAwareness, !!pGetProcessDpiAwareness);
 #endif
@@ -723,8 +728,9 @@ win_adapt_term_size(bool sync_size_with_font, bool scale_font_with_size)
       // bigger
       //   ? font_size * rows0 * cols0 / (term.rows * term.cols)
       //   : font_size * rows0 * cols0 / (term.rows * term.cols);
-      trace_resize(("term size %d %d -> %d %d\n", term.rows, term.cols, rows0, cols0));
-      trace_resize(("font size %d -> %d\n", font_size, font_size1));
+
+    trace_resize(("term size %d %d -> %d %d\n", term.rows, term.cols, rows0, cols0));
+    trace_resize(("font size %d -> %d\n", font_size, font_size1));
 
     if (font_size1 != font_size)
       win_set_font_size(font_size1, false);
@@ -1132,7 +1138,7 @@ static struct {
       return ew || eh;
     }
     when WM_SIZE: {
-      trace_resize(("# WM_SIZE (resizing %d) VK_SHIFT %02X\n", resizing, GetKeyState(VK_SHIFT)));
+      trace_resize(("# WM_SIZE (resizing %d) VK_SHIFT %02X %d\n", resizing, GetKeyState(VK_SHIFT), zoom_token));
       if (wp == SIZE_RESTORED && win_is_fullscreen)
         clear_fullscreen();
       else if (wp == SIZE_MAXIMIZED && go_fullscr_on_max) {
@@ -1157,6 +1163,7 @@ static struct {
 #endif
         bool scale_font = (cfg.zoom_font_with_window || zoom_token > 2)
                           && (zoom_token > 0) && (GetKeyState(VK_SHIFT) & 0x80);
+
         win_adapt_term_size(false, scale_font);
         if (zoom_token > 0)
           zoom_token = zoom_token >> 1;
@@ -1168,18 +1175,31 @@ static struct {
       win_update_menus();
       return 0;
     when WM_DPICHANGED:
-#ifdef debug_dpi
-      printf("WM_DPICHANGED %d\n", per_monitor_dpi_aware);
-#endif
       if (per_monitor_dpi_aware) {
         LPRECT r = (LPRECT) lp;
+        WORD x_dpi = LOWORD(wp);
+
+#ifdef debug_dpi
+        printf("WM_DPICHANGED %d L,T,R,B=%d,%d,%d,%d WxH=%dx%d, %d -> %d\n", per_monitor_dpi_aware, r->left, r->top, r->right, r->bottom, r->right - r->left, r->bottom - r->top, last_dpi, x_dpi);
+#endif
+        if (last_dpi > 0) {
+          int font_size1 = round((double)font_size * x_dpi / last_dpi);
+#ifdef debug_dpi
+          printf("font_size: %d -> %d\n", font_size, font_size1);
+#endif
+          win_set_font_size(font_size1, false);
+        }
+        last_dpi = x_dpi;
+
+#ifdef debug_dpi
+        printf("SM_CXVSCROLL %d\n", GetSystemMetrics(SM_CXVSCROLL));
+#endif
+
         SetWindowPos(wnd, 0,
           r->left, r->top, r->right - r->left, r->bottom - r->top,
           SWP_NOZORDER | SWP_NOOWNERZORDER | SWP_NOACTIVATE);
+
         win_adapt_term_size(false, true);
-#ifdef debug_dpi
-        printf("SM_CXVSCROLL %d\n", GetSystemMetrics(SM_CXVSCROLL));
-#endif
         return 0;
       }
       break;
@@ -1912,7 +1932,7 @@ main(int argc, char *argv[])
 
 #define dont_debug_position
 #ifdef debug_position
-#define printpos(tag, x, y, mon)	printf("%s %d %d (%ld %ld %ld %ld)\n", tag, x, y, mon.left, mon.top, mon.right, mon.bottom);
+#define printpos(tag, x, y, mon)  printf("%s %d %d (%ld %ld %ld %ld)\n", tag, x, y, mon.left, mon.top, mon.right, mon.bottom);
 #else
 #define printpos(tag, x, y, mon)
 #endif