Make sure zooming via mouse goes back to 1.0

Add a check that snaps the value to 1 if close enough.

Fixes #1822

Author: Flamefire

libs/s25main/gameData/GuiConsts.h

@@ -1,12 +1,12 @@
-// Copyright (C) 2005 - 2021 Settlers Freaks (sf-team at siedler25.org)
+// Copyright (C) 2005 - 2025 Settlers Freaks (sf-team at siedler25.org)
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
 #include <array>
 
-const std::array<float, 7> SUPPRESS_UNUSED ZOOM_FACTORS = {{0.5f, 0.75f, 1.f, 1.25f, 1.5f, 2.f, 3.f}};
-const size_t ZOOM_DEFAULT_INDEX = 2;
-const float ZOOM_ACCELERATION = 0.001f;
-const float ZOOM_WHEEL_INCREMENT = 0.03f;
+constexpr std::array<float, 7> SUPPRESS_UNUSED ZOOM_FACTORS = {{0.5f, 0.75f, 1.f, 1.25f, 1.5f, 2.f, 3.f}};
+constexpr size_t ZOOM_DEFAULT_INDEX = 2;
+constexpr float ZOOM_ACCELERATION = 0.001f;
+constexpr float ZOOM_WHEEL_INCREMENT = 0.03f;

libs/s25main/world/GameWorldView.cpp

@@ -96,6 +96,8 @@ void GameWorldView::SetZoomFactor(float zoomFactor, bool smoothTransition /* = t
         targetZoomFactor_ = ZOOM_FACTORS.back();
     else
         targetZoomFactor_ = zoomFactor;
+    if(targetZoomFactor_ > 1 - ZOOM_WHEEL_INCREMENT && targetZoomFactor_ < 1 + ZOOM_WHEEL_INCREMENT)
+        targetZoomFactor_ = 1.f; // Snap to 100%
     if(!smoothTransition)
     {
         zoomFactor_ = targetZoomFactor_;

tests/s25Main/integration/testDskGameInterface.cpp

@@ -1,4 +1,4 @@
-// Copyright (C) 2005 - 2021 Settlers Freaks (sf-team at siedler25.org)
+// Copyright (C) 2005 - 2025 Settlers Freaks (sf-team at siedler25.org)
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -14,6 +14,8 @@
 #include "uiHelper/uiHelpers.hpp"
 #include "worldFixtures/CreateEmptyWorld.h"
 #include "worldFixtures/WorldFixture.h"
+#include "gameData/GuiConsts.h"
+#include "rttr/test/random.hpp"
 #include <boost/test/unit_test.hpp>
 
 // LCOV_EXCL_START
@@ -36,6 +38,9 @@ struct dskGameInterfaceMock : public dskGameInterface
     void Msg_PaintBefore() override {}
     void Msg_PaintAfter() override {}
     using dskGameInterface::actionwindow;
+    using dskGameInterface::Msg_KeyDown;
+    using dskGameInterface::Msg_WheelDown;
+    using dskGameInterface::Msg_WheelUp;
 };
 struct GameInterfaceFixture : uiHelper::Fixture
 {
@@ -227,4 +232,67 @@ BOOST_FIXTURE_TEST_CASE(IwActionClose, GameInterfaceFixture)
     BOOST_TEST_REQUIRE(gameDesktop->actionwindow == nullptr);
 }
 
+BOOST_FIXTURE_TEST_CASE(Zooming, GameInterfaceFixture)
+{
+    const KeyEvent zoomInEv{KeyType::Char, 'z'};
+    const KeyEvent zoomOutEv{KeyType::Char, 'Z'};
+    const KeyEvent zoomDefaultEv{KeyType::Char, 'z', true, false, false}; // Ctrl+z
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[ZOOM_DEFAULT_INDEX]);
+    for(size_t i = ZOOM_DEFAULT_INDEX + 1; i < ZOOM_FACTORS.size(); i++)
+    {
+        gameDesktop->Msg_KeyDown(zoomInEv);
+        BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[i]);
+    }
+    // Wrap around
+    gameDesktop->Msg_KeyDown(zoomInEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[0]);
+    gameDesktop->Msg_KeyDown(zoomInEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[1]);
+
+    gameDesktop->Msg_KeyDown(zoomOutEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[0]);
+    gameDesktop->Msg_KeyDown(zoomOutEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS.back());
+
+    gameDesktop->Msg_KeyDown(zoomDefaultEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[ZOOM_DEFAULT_INDEX]);
+
+    gameDesktop->Msg_WheelDown({});
+    auto curZoom = view->GetCurrentTargetZoomFactor();
+    BOOST_TEST(curZoom < ZOOM_FACTORS[ZOOM_DEFAULT_INDEX]);
+    BOOST_TEST(curZoom > ZOOM_FACTORS[ZOOM_DEFAULT_INDEX - 1]);
+    // Go to prev index
+    gameDesktop->Msg_KeyDown(zoomOutEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[ZOOM_DEFAULT_INDEX - 1]);
+
+    gameDesktop->Msg_KeyDown(zoomDefaultEv);
+    gameDesktop->Msg_WheelUp({});
+    curZoom = view->GetCurrentTargetZoomFactor();
+    BOOST_TEST(curZoom > ZOOM_FACTORS[ZOOM_DEFAULT_INDEX]);
+    BOOST_TEST(curZoom < ZOOM_FACTORS[ZOOM_DEFAULT_INDEX + 1]);
+    // Go to next index
+    gameDesktop->Msg_KeyDown(zoomInEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[ZOOM_DEFAULT_INDEX + 1]);
+
+    gameDesktop->Msg_WheelDown({});
+    curZoom = view->GetCurrentTargetZoomFactor();
+    BOOST_TEST(curZoom > ZOOM_FACTORS[ZOOM_DEFAULT_INDEX]);
+    BOOST_TEST(curZoom < ZOOM_FACTORS[ZOOM_DEFAULT_INDEX + 1]);
+    // Go to prev index
+    gameDesktop->Msg_KeyDown(zoomOutEv);
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == ZOOM_FACTORS[ZOOM_DEFAULT_INDEX]);
+
+    // Zoom in and out gets to 1.0 (default)
+    static_assert(ZOOM_FACTORS[ZOOM_DEFAULT_INDEX] == 1.f);
+    gameDesktop->Msg_WheelUp({});
+    gameDesktop->Msg_WheelDown({});
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == 1.f);
+    const auto numZoom = rttr::test::randomValue(2, 10);
+    for(int i = 0; i < numZoom; i++)
+        gameDesktop->Msg_WheelDown({});
+    for(int i = 0; i < numZoom; i++)
+        gameDesktop->Msg_WheelUp({});
+    BOOST_TEST(view->GetCurrentTargetZoomFactor() == 1.f);
+}
+
 BOOST_AUTO_TEST_SUITE_END()