From a5622af68d792899e4de6c79c848d15161fbc511 Mon Sep 17 00:00:00 2001
From: Jonathan Marler <johnnymarler@gmail.com>
Date: Tue, 14 Jan 2025 09:19:12 -0700
Subject: [PATCH] win32 gui: keep window aspect ratio during resizing

Now instead of snapping to a size after releasing the mouse from resizing
the window, the window will incrementally snap to a good size while the
window is being resized.
---
 src/win32/gui.zig | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/win32/gui.zig b/src/win32/gui.zig
index bc9091a..e880972 100644
--- a/src/win32/gui.zig
+++ b/src/win32/gui.zig
@@ -198,7 +198,6 @@ const State = struct {
     pid: thespian.pid,
     render_state: render.WindowState,
     scroll_delta: isize = 0,
-    last_sizing_edge: ?win32.WPARAM = null,
     bounds: ?WindowBounds = null,
 };
 fn stateFromHwnd(hwnd: win32.HWND) *State {
@@ -1036,15 +1035,17 @@ fn WndProc(
             return 0;
         },
         win32.WM_SIZING => {
+            const rect: *win32.RECT = @ptrFromInt(@as(usize, @bitCast(lparam)));
+            const dpi = win32.dpiFromHwnd(hwnd);
+            const font = getFont(dpi, getFontSize(), getFontFace());
+            const cell_size = font.getCellSize(i32);
+            const new_rect = calcWindowRect(dpi, rect.*, wparam, cell_size);
             const state = stateFromHwnd(hwnd);
-            state.last_sizing_edge = wparam;
-            return 0;
-        },
-        win32.WM_EXITSIZEMOVE => {
-            const state = stateFromHwnd(hwnd);
-            state.bounds = null;
-            updateWindowSize(hwnd, state.last_sizing_edge, &state.bounds);
-            state.last_sizing_edge = null;
+            state.bounds = .{
+                .token = new_rect,
+                .rect = rect.*,
+            };
+            rect.* = new_rect;
             return 0;
         },
         win32.WM_DISPLAYCHANGE => {