Recalculate window size after a screen buffer resize

.github/actions/spelling/expect/expect.txt

@@ -1411,6 +1411,7 @@ rerasterize
 rescap
 RESETCONTENT
 resheader
+resizewindowtest
 resmimetype
 resultmacros
 resw

OpenConsole.slnx

@@ -894,6 +894,18 @@
       <Build Solution="Fuzzing|ARM64" Project="false" />
       <Build Solution="Fuzzing|x86" Project="false" />
     </Project>
+    <Project Path="src/tools/resizewindowtest/resizewindowtest.vcxproj" Id="a8020ad3-2ef5-48f1-be5e-91189fec5351">
+      <BuildType Solution="AuditMode|ARM64" Project="Release" />
+      <BuildType Solution="AuditMode|x64" Project="Release" />
+      <BuildType Solution="AuditMode|x86" Project="Release" />
+      <Platform Solution="*|Any CPU" Project="Win32" />
+      <Build Solution="*|Any CPU" Project="false" />
+      <Build Solution="AuditMode|ARM64" Project="false" />
+      <Build Solution="AuditMode|x64" Project="false" />
+      <Build Solution="AuditMode|x86" Project="false" />
+      <Build Solution="Fuzzing|ARM64" Project="false" />
+      <Build Solution="Fuzzing|x86" Project="false" />
+    </Project>
     <Project Path="src/tools/closetest/CloseTest.vcxproj" Id="c7a6a5d9-60be-4aeb-a5f6-afe352f86cbb">
       <BuildType Solution="AuditMode|ARM64" Project="Release" />
       <BuildType Solution="AuditMode|x64" Project="Release" />

src/host/screenInfo.cpp

@@ -1402,6 +1402,19 @@ NT_CATCH_RETURN()
         if (fDoScrollBarUpdate)
         {
             UpdateScrollBars();
+
+            // The window's outer pixel rect may have been sized to reserve
+            // room for a scroll bar based on the *previous* buffer size (see
+            // Window::s_CalculateWindowRect's buffer-vs-window comparison).
+            // UpdateScrollBars() above only hides/shows the scroll bar
+            // control itself - it doesn't shrink or grow the window to match,
+            // so without this, a buffer resize that removes (or newly
+            // creates) a size mismatch leaves stale, unpainted space where a
+            // scroll bar used to be reserved. Callers that already trigger a
+            // window resize of their own right after this (the
+            // fDoScrollBarUpdate == false cases) skip this to avoid posting
+            // it twice.
+            PostUpdateWindowSize();
         }
         ScreenBufferSizeChange(coordNewScreenSize);
     }

src/tools/resizewindowtest/main.cpp

@@ -0,0 +1,208 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+// Reproduces a three-step console resize sequence some clients use to
+// safely resize a console window/buffer pair in either direction (a window
+// can never be made bigger than the current buffer, and a buffer can never
+// be made smaller than the current window, so the safe order is: shrink the
+// window first if needed, resize the buffer, then grow the window back up
+// if the requested size is bigger than what it was shrunk to):
+//
+//   1. SetConsoleWindowInfo()       - shrink the window if it's currently
+//                                     bigger than the requested size
+//   2. SetConsoleScreenBufferSize() - resize the buffer to the requested size
+//   3. SetConsoleWindowInfo()       - grow the window back up to the
+//                                     requested size, but only if step 1
+//                                     didn't already get it there
+//
+// Step 3 is skipped whenever the requested size doesn't exceed the window's
+// size from before this sequence started. That's exactly the case that
+// exposes the bug this tool validates: after step 2, the window's outer
+// pixel rect can be left holding pixel space that was reserved for a scroll
+// bar which is no longer needed, and without step 3 nothing else
+// re-evaluates that rect (see ResizeScreenBuffer's PostUpdateWindowSize()
+// call in src/host/screenInfo.cpp).
+//
+// Usage: resizewindowtest.exe [width height]   (defaults to 80x25)
+//
+// After resizing, the whole buffer is filled with a solid color and the
+// resulting buffer/window/max-window sizes (from GetConsoleScreenBufferInfo)
+// are written to the window title and to resizewindowtest.log next to the
+// executable. Watch the right and bottom edges of the window: any strip of
+// unpainted background left between the filled content and the window
+// frame indicates the bug - even though the log will show the buffer and
+// window character dimensions matching exactly.
+
+#include <windows.h>
+#include <conio.h>
+#include <cstdio>
+#include <cstdlib>
+
+namespace
+{
+    HANDLE g_hOut;
+    FILE* g_log;
+
+    void WindowSize(int w, int h, int top, int left)
+    {
+        SMALL_RECT rect;
+        rect.Top = static_cast<SHORT>(top);
+        rect.Left = static_cast<SHORT>(left);
+        rect.Bottom = static_cast<SHORT>(top + h - 1);
+        rect.Right = static_cast<SHORT>(left + w - 1);
+
+        if (!SetConsoleWindowInfo(g_hOut, TRUE, &rect))
+        {
+            fprintf(g_log, "SetConsoleWindowInfo(%d,%d @ %d,%d) FAILED: %lu\n", w, h, top, left, GetLastError());
+        }
+        else
+        {
+            fprintf(g_log, "SetConsoleWindowInfo(%d,%d @ %d,%d) OK\n", w, h, top, left);
+        }
+    }
+
+    void BufferSize(int w, int h)
+    {
+        COORD size;
+        size.X = static_cast<SHORT>(w);
+        size.Y = static_cast<SHORT>(h);
+
+        if (!SetConsoleScreenBufferSize(g_hOut, size))
+        {
+            fprintf(g_log, "SetConsoleScreenBufferSize(%d,%d) FAILED: %lu\n", w, h, GetLastError());
+        }
+        else
+        {
+            fprintf(g_log, "SetConsoleScreenBufferSize(%d,%d) OK\n", w, h);
+        }
+    }
+
+    // The shrink/resize/grow sequence described at the top of this file.
+    void ResizeWindow(int w, int h)
+    {
+        CONSOLE_SCREEN_BUFFER_INFO info;
+        if (!GetConsoleScreenBufferInfo(g_hOut, &info))
+        {
+            fprintf(g_log, "GetConsoleScreenBufferInfo (1) FAILED: %lu\n", GetLastError());
+            return;
+        }
+
+        const auto oldTop = info.srWindow.Top;
+        const auto oldLeft = info.srWindow.Left;
+        const auto oldWindowWidth = info.srWindow.Right - info.srWindow.Left + 1;
+        const auto oldWindowHeight = info.srWindow.Bottom - info.srWindow.Top + 1;
+
+        fprintf(g_log, "ResizeWindow(%d,%d): oldWindow=%dx%d oldBuffer=%dx%d\n",
+                w, h, oldWindowWidth, oldWindowHeight, info.dwSize.X, info.dwSize.Y);
+
+        // 1. Shrink the window first if it's bigger than the target in
+        //    either dimension - a buffer can never be resized smaller than
+        //    the window currently displaying it.
+        if (info.srWindow.Bottom >= h || info.srWindow.Right >= w)
+        {
+            WindowSize(min(w, oldWindowWidth), min(h, oldWindowHeight), 0, 0);
+        }
+
+        // 2. Resize the buffer to the target size.
+        BufferSize(w, h);
+
+        if (!GetConsoleScreenBufferInfo(g_hOut, &info))
+        {
+            fprintf(g_log, "GetConsoleScreenBufferInfo (2) FAILED: %lu\n", GetLastError());
+            return;
+        }
+        fprintf(g_log, "  dwMaximumWindowSize = %dx%d\n", info.dwMaximumWindowSize.X, info.dwMaximumWindowSize.Y);
+
+        auto newLeft = w - info.dwMaximumWindowSize.X;
+        if (newLeft > 0)
+        {
+            w = info.dwMaximumWindowSize.X;
+        }
+        else
+        {
+            newLeft = 0;
+        }
+
+        auto newTop = h - info.dwMaximumWindowSize.Y;
+        if (newTop > 0)
+        {
+            h = info.dwMaximumWindowSize.Y;
+        }
+        else
+        {
+            newTop = 0;
+        }
+
+        // 3. Grow the window back up to the target size, only if step 1
+        //    didn't already get it there. This is the step that's skipped
+        //    when the requested size doesn't exceed the window's original
+        //    size - the case this tool is meant to exercise.
+        if (w > oldWindowWidth || h > oldWindowHeight)
+        {
+            WindowSize(w, h, min(newTop, oldTop), min(newLeft, oldLeft));
+        }
+    }
+
+    void FillAndReport(int requestedWidth, int requestedHeight)
+    {
+        CONSOLE_SCREEN_BUFFER_INFO info;
+        GetConsoleScreenBufferInfo(g_hOut, &info);
+
+        const COORD origin{ 0, 0 };
+        const DWORD cellCount = static_cast<DWORD>(info.dwSize.X) * static_cast<DWORD>(info.dwSize.Y);
+        const WORD attr = BACKGROUND_BLUE | BACKGROUND_INTENSITY | FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE;
+        DWORD written;
+
+        FillConsoleOutputCharacterW(g_hOut, L' ', cellCount, origin, &written);
+        FillConsoleOutputAttribute(g_hOut, attr, cellCount, origin, &written);
+
+        char title[256];
+        sprintf_s(title,
+                  "req=%dx%d buffer=%dx%d window=%dx%d (col %d-%d, row %d-%d) maxWin=%dx%d",
+                  requestedWidth, requestedHeight,
+                  info.dwSize.X, info.dwSize.Y,
+                  info.srWindow.Right - info.srWindow.Left + 1,
+                  info.srWindow.Bottom - info.srWindow.Top + 1,
+                  info.srWindow.Left, info.srWindow.Right,
+                  info.srWindow.Top, info.srWindow.Bottom,
+                  info.dwMaximumWindowSize.X, info.dwMaximumWindowSize.Y);
+        SetConsoleTitleA(title);
+        fprintf(g_log, "%s\n", title);
+
+        const char* msg = "resizewindowtest - see title bar / resizewindowtest.log - press any key";
+        WriteConsoleOutputCharacterA(g_hOut, msg, static_cast<DWORD>(strlen(msg)), origin, &written);
+    }
+}
+
+int __cdecl wmain(int argc, WCHAR* argv[])
+{
+    int width = 80;
+    int height = 25;
+    if (argc >= 3)
+    {
+        width = _wtoi(argv[1]);
+        height = _wtoi(argv[2]);
+    }
+
+    g_log = fopen("resizewindowtest.log", "w");
+    if (!g_log)
+    {
+        g_log = stderr;
+    }
+
+    g_hOut = GetStdHandle(STD_OUTPUT_HANDLE);
+    if (g_hOut == INVALID_HANDLE_VALUE || g_hOut == nullptr)
+    {
+        fprintf(g_log, "GetStdHandle failed: %lu\n", GetLastError());
+        return 1;
+    }
+
+    fprintf(g_log, "Resizing to %d x %d...\n", width, height);
+    ResizeWindow(width, height);
+
+    FillAndReport(width, height);
+    fflush(g_log);
+
+    _getch();
+    return 0;
+}

src/tools/resizewindowtest/resizewindowtest.vcxproj

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{A8020AD3-2EF5-48F1-BE5E-91189FEC5351}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>resizewindowtest</RootNamespace>
+    <ProjectName>resizewindowtest</ProjectName>
+    <TargetName>resizewindowtest</TargetName>
+    <ConfigurationType>Application</ConfigurationType>
+  </PropertyGroup>
+  <Import Project="..\..\common.build.pre.props" />
+  <ItemGroup>
+    <ClCompile Include="main.cpp" />
+  </ItemGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <PreprocessorDefinitions>_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <!-- Careful reordering these. Some default props (contained in these files) are order sensitive. -->
+  <Import Project="..\..\common.build.post.props" />
+  <Import Project="..\..\common.build.tests.props" />
+</Project>

src/tools/resizewindowtest/resizewindowtest.vcxproj.filters

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source Files">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+    <Filter Include="Header Files">
+      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
+      <Extensions>h;hh;hpp;hxx;hm;inl;inc;xsd</Extensions>
+    </Filter>
+    <Filter Include="Resource Files">
+      <UniqueIdentifier>{67DA6AB6-F800-4c08-8B7A-83BB121AAD01}</UniqueIdentifier>
+      <Extensions>rc;ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe;resx;tiff;tif;png;wav;mfcribbon-ms</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="main.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+  </ItemGroup>
+</Project>