[core] Group Map LatLngBounds, min and max zoom methods

Group bounds, minimum and maximum zoom related methods together using
the new BoundOptions.

v2: Document that getBounds() initializes all optional fields.
  - Add test for getBounds() on a map with default values.

11 files changed, 123 insertions, 56 deletions

diff --git a/include/mbgl/map/bound_options.hpp b/include/mbgl/map/bound_options.hpp
new file mode 100644
index 0000000000..69d353a301
--- /dev/null
+++ b/include/mbgl/map/bound_options.hpp
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <mbgl/util/geo.hpp>
+#include <mbgl/util/optional.hpp>
+
+namespace mbgl {
+
+/**
+ * @brief Holds options to limit what parts of a map are visible. All fields are
+ * optional.
+ */
+struct BoundOptions {
+    /// Sets the latitude and longitude bounds to which the camera center are constrained
+    BoundOptions& withLatLngBounds(LatLngBounds b) { bounds = b; return *this; }
+    /// Sets the minimum zoom level
+    BoundOptions& withMinZoom(double z) { minZoom = z; return *this; }
+    /// Sets the maximum zoom level
+    BoundOptions& withMaxZoom(double z) { maxZoom = z; return *this; }
+
+    /// Constrain the center of the camera to be within these bounds.
+    optional<LatLngBounds> bounds;
+
+    /// Maximum zoom level allowed.
+    optional<double> maxZoom;
+
+    /// Minimum zoom level allowed.
+    optional<double> minZoom;
+};
+
+}  // namespace mbgl
diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 93e5190f99..b4f60a19ba 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -2,6 +2,7 @@
 
 #include <mbgl/util/optional.hpp>
 #include <mbgl/util/chrono.hpp>
+#include <mbgl/map/bound_options.hpp>
 #include <mbgl/map/map_observer.hpp>
 #include <mbgl/map/map_options.hpp>
 #include <mbgl/map/mode.hpp>
@@ -76,13 +77,15 @@ public:
     CameraOptions cameraForGeometry(const Geometry<double>&, const EdgeInsets&, optional<double> bearing = {}, optional<double> pitch = {}) const;
     LatLngBounds latLngBoundsForCamera(const CameraOptions&) const;
 
-    // Bounds
-    void setLatLngBounds(LatLngBounds);
-    LatLngBounds getLatLngBounds() const;
-    void setMinZoom(double);
-    double getMinZoom() const;
-    void setMaxZoom(double);
-    double getMaxZoom() const;
+    /// @name Bounds
+    /// @{
+
+    void setBounds(const BoundOptions& options);
+
+    /// Returns the current map bound options. All optional fields in BoundOptions are set.
+    BoundOptions getBounds() const;
+
+    /// @}
 
     // North Orientation
     void setNorthOrientation(NorthOrientation);
diff --git a/platform/android/src/native_map_view.cpp b/platform/android/src/native_map_view.cpp
index 83a158efa9..3a4e2014ba 100755
--- a/platform/android/src/native_map_view.cpp
+++ b/platform/android/src/native_map_view.cpp
@@ -287,11 +287,13 @@ void NativeMapView::setStyleJson(jni::JNIEnv& env, const jni::String& json) {
 }
 
 void NativeMapView::setLatLngBounds(jni::JNIEnv& env, const jni::Object<mbgl::android::LatLngBounds>& jBounds) {
+    mbgl::BoundOptions bounds;
     if (jBounds) {
-        map->setLatLngBounds(mbgl::android::LatLngBounds::getLatLngBounds(env, jBounds));
+        bounds.withLatLngBounds(mbgl::android::LatLngBounds::getLatLngBounds(env, jBounds));
     } else {
-        map->setLatLngBounds(mbgl::LatLngBounds::world());
+        bounds.withLatLngBounds(mbgl::LatLngBounds::world());
     }
+    map->setBounds(bounds);
 }
 
 void NativeMapView::cancelTransitions(jni::JNIEnv&) {
@@ -424,19 +426,19 @@ void NativeMapView::resetZoom(jni::JNIEnv&) {
 }
 
 void NativeMapView::setMinZoom(jni::JNIEnv&, jni::jdouble zoom) {
-    map->setMinZoom(zoom);
+    map->setBounds(BoundOptions().withMinZoom(zoom));
 }
 
 jni::jdouble NativeMapView::getMinZoom(jni::JNIEnv&) {
-    return map->getMinZoom();
+    return *map->getBounds().minZoom;
 }
 
 void NativeMapView::setMaxZoom(jni::JNIEnv&, jni::jdouble zoom) {
-    map->setMaxZoom(zoom);
+    map->setBounds(BoundOptions().withMaxZoom(zoom));
 }
 
 jni::jdouble NativeMapView::getMaxZoom(jni::JNIEnv&) {
-    return map->getMaxZoom();
+    return *map->getBounds().maxZoom;
 }
 
 void NativeMapView::rotateBy(jni::JNIEnv&, jni::jdouble sx, jni::jdouble sy, jni::jdouble ex, jni::jdouble ey, jni::jlong duration) {
diff --git a/platform/glfw/glfw_view.cpp b/platform/glfw/glfw_view.cpp
index 86833da6ee..e768851a53 100644
--- a/platform/glfw/glfw_view.cpp
+++ b/platform/glfw/glfw_view.cpp
@@ -296,7 +296,7 @@ void GLFWView::onKey(GLFWwindow *window, int key, int /*scancode*/, int action,
             mbgl::LatLngBounds bound = bounds[nextBound++];
             nextBound = nextBound % bounds.size();
 
-            view->map->setLatLngBounds(bound);
+            view->map->setBounds(mbgl::BoundOptions().withLatLngBounds(bound));
 
             if (bound == mbgl::LatLngBounds::unbounded()) {
                 view->map->removeAnnotation(boundAnnotationID);
diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index f393dec0c1..692da30f04 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -1661,7 +1661,7 @@ public:
             newScale += scale / (velocity * duration) * 0.1;
         }
 
-        if (newScale <= 0 || log2(newScale) < self.mbglMap.getMinZoom())
+        if (newScale <= 0 || log2(newScale) < *self.mbglMap.getBounds().minZoom)
         {
             velocity = 0;
         }
@@ -1927,7 +1927,7 @@ public:
 
     if ( ! self.isZoomEnabled) return;
 
-    if ([self zoomLevel] == self.mbglMap.getMinZoom()) return;
+    if ([self zoomLevel] == *self.mbglMap.getBounds().minZoom) return;
 
     [self cancelTransitions];
 
@@ -1979,7 +1979,7 @@ public:
     {
         CGFloat distance = [quickZoom locationInView:quickZoom.view].y - self.quickZoomStart;
 
-        CGFloat newZoom = MAX(log2f(self.scale) + (distance / 75), self.mbglMap.getMinZoom());
+        CGFloat newZoom = MAX(log2f(self.scale) + (distance / 75), *self.mbglMap.getBounds().minZoom);
 
         if ([self zoomLevel] == newZoom) return;
 
@@ -3251,23 +3251,23 @@ public:
 - (void)setMinimumZoomLevel:(double)minimumZoomLevel
 {
     MGLLogDebug(@"Setting minimumZoomLevel: %f", minimumZoomLevel);
-    self.mbglMap.setMinZoom(minimumZoomLevel);
+    self.mbglMap.setBounds(mbgl::BoundOptions().withMinZoom(minimumZoomLevel));
 }
 
 - (double)minimumZoomLevel
 {
-    return self.mbglMap.getMinZoom();
+    return *self.mbglMap.getBounds().minZoom;
 }
 
 - (void)setMaximumZoomLevel:(double)maximumZoomLevel
 {
     MGLLogDebug(@"Setting maximumZoomLevel: %f", maximumZoomLevel);
-    self.mbglMap.setMaxZoom(maximumZoomLevel);
+    self.mbglMap.setBounds(mbgl::BoundOptions().withMaxZoom(maximumZoomLevel));
 }
 
 - (double)maximumZoomLevel
 {
-    return self.mbglMap.getMaxZoom();
+    return *self.mbglMap.getBounds().maxZoom;
 }
 
 - (MGLCoordinateBounds)visibleCoordinateBounds
@@ -5847,7 +5847,7 @@ public:
 
 - (CGFloat)currentMinimumZoom
 {
-    return fmaxf(self.mbglMap.getMinZoom(), MGLMinimumZoom);
+    return fmaxf(*self.mbglMap.getBounds().minZoom, MGLMinimumZoom);
 }
 
 - (BOOL)isRotationAllowed
diff --git a/platform/macos/src/MGLMapView.mm b/platform/macos/src/MGLMapView.mm
index 054b91d44c..320abf740c 100644
--- a/platform/macos/src/MGLMapView.mm
+++ b/platform/macos/src/MGLMapView.mm
@@ -328,7 +328,7 @@ public:
     mbgl::CameraOptions options;
     options.center = mbgl::LatLng(0, 0);
     options.padding = MGLEdgeInsetsFromNSEdgeInsets(self.contentInsets);
-    options.zoom = _mbglMap->getMinZoom();
+    options.zoom = *_mbglMap->getBounds().minZoom;
     _mbglMap->jumpTo(options);
     _pendingLatitude = NAN;
     _pendingLongitude = NAN;
@@ -1094,21 +1094,21 @@ public:
 - (void)setMinimumZoomLevel:(double)minimumZoomLevel
 {
     MGLLogDebug(@"Setting minimumZoomLevel: %f", minimumZoomLevel);
-    _mbglMap->setMinZoom(minimumZoomLevel);
+    _mbglMap->setBounds(mbgl::BoundOptions().withMinZoom(minimumZoomLevel));
 }
 
 - (void)setMaximumZoomLevel:(double)maximumZoomLevel
 {
     MGLLogDebug(@"Setting maximumZoomLevel: %f", maximumZoomLevel);
-    _mbglMap->setMaxZoom(maximumZoomLevel);
+    _mbglMap->setBounds(mbgl::BoundOptions().withMaxZoom(maximumZoomLevel));
 }
 
 - (double)maximumZoomLevel {
-    return _mbglMap->getMaxZoom();
+    return *_mbglMap->getBounds().maxZoom;
 }
 
 - (double)minimumZoomLevel {
-    return _mbglMap->getMinZoom();
+    return *_mbglMap->getBounds().minZoom;
 }
 
 /// Respond to a click on the zoom control.
diff --git a/platform/qt/src/qmapboxgl.cpp b/platform/qt/src/qmapboxgl.cpp
index 990e70c97f..b05c82a783 100644
--- a/platform/qt/src/qmapboxgl.cpp
+++ b/platform/qt/src/qmapboxgl.cpp
@@ -765,7 +765,7 @@ void QMapboxGL::setZoom(double zoom_)
 */
 double QMapboxGL::minimumZoom() const
 {
-    return d_ptr->mapObj->getMinZoom();
+    return *d_ptr->mapObj->getBounds().minZoom;
 }
 
 /*!
@@ -775,7 +775,7 @@ double QMapboxGL::minimumZoom() const
 */
 double QMapboxGL::maximumZoom() const
 {
-    return d_ptr->mapObj->getMaxZoom();
+    return *d_ptr->mapObj->getBounds().maxZoom;
 }
 
 /*!
diff --git a/src/core-files.json b/src/core-files.json
index 8915ebc49d..6415f03182 100644
--- a/src/core-files.json
+++ b/src/core-files.json
@@ -328,6 +328,7 @@
         "mbgl/layermanager/line_layer_factory.hpp": "include/mbgl/layermanager/line_layer_factory.hpp",
         "mbgl/layermanager/raster_layer_factory.hpp": "include/mbgl/layermanager/raster_layer_factory.hpp",
         "mbgl/layermanager/symbol_layer_factory.hpp": "include/mbgl/layermanager/symbol_layer_factory.hpp",
+        "mbgl/map/bound_options.hpp": "include/mbgl/map/bound_options.hpp",
         "mbgl/map/camera.hpp": "include/mbgl/map/camera.hpp",
         "mbgl/map/change.hpp": "include/mbgl/map/change.hpp",
         "mbgl/map/map.hpp": "include/mbgl/map/map.hpp",
diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index e45d4b85f2..f545fc8095 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -275,36 +275,41 @@ LatLngBounds Map::latLngBoundsForCamera(const CameraOptions& camera) const {
 
 #pragma mark - Bounds
 
-LatLngBounds Map::getLatLngBounds() const {
-    return impl->transform.getState().getLatLngBounds();
-}
+void Map::setBounds(const BoundOptions& options) {
+    bool changeCamera = false;
+    CameraOptions cameraOptions;
 
-void Map::setLatLngBounds(LatLngBounds bounds) {
-    impl->cameraMutated = true;
-    impl->transform.setLatLngBounds(std::move(bounds));
-    impl->onUpdate();
-}
+    if (options.bounds) {
+        changeCamera = true;
+        impl->transform.setLatLngBounds(*options.bounds);
+    }
 
-void Map::setMinZoom(const double minZoom) {
-    impl->transform.setMinZoom(minZoom);
-    if (impl->transform.getZoom() < minZoom) {
-        jumpTo(CameraOptions().withZoom(minZoom));
+    if (options.minZoom) {
+        impl->transform.setMinZoom(*options.minZoom);
+        if (impl->transform.getZoom() < *options.minZoom) {
+            changeCamera = true;
+            cameraOptions.withZoom(*options.minZoom);
+        }
     }
-}
 
-double Map::getMinZoom() const {
-    return impl->transform.getState().getMinZoom();
-}
+    if (options.maxZoom) {
+        impl->transform.setMaxZoom(*options.maxZoom);
+        if (impl->transform.getZoom() > *options.maxZoom) {
+            changeCamera = true;
+            cameraOptions.withZoom(*options.maxZoom);
+        }
+    }
 
-void Map::setMaxZoom(const double maxZoom) {
-    impl->transform.setMaxZoom(maxZoom);
-    if (impl->transform.getZoom() > maxZoom) {
-        jumpTo(CameraOptions().withZoom(maxZoom));
+    if (changeCamera) {
+        jumpTo(cameraOptions);
     }
 }
 
-double Map::getMaxZoom() const {
-    return impl->transform.getState().getMaxZoom();
+BoundOptions Map::getBounds() const {
+    return BoundOptions()
+        .withLatLngBounds(impl->transform.getState().getLatLngBounds())
+        .withMinZoom(impl->transform.getState().getMinZoom())
+        .withMaxZoom(impl->transform.getState().getMaxZoom());
 }
 
 #pragma mark - Size
diff --git a/test/api/annotations.test.cpp b/test/api/annotations.test.cpp
index 89ce357d84..aad85f8d57 100644
--- a/test/api/annotations.test.cpp
+++ b/test/api/annotations.test.cpp
@@ -85,7 +85,7 @@ TEST(Annotations, LineAnnotation) {
     test.map.addAnnotation(annotation);
     test.checkRendering("line_annotation");
 
-    test.map.jumpTo(CameraOptions().withZoom(test.map.getMaxZoom()));
+    test.map.jumpTo(CameraOptions().withZoom(*test.map.getBounds().maxZoom));
     test.checkRendering("line_annotation_max_zoom");
 }
 
@@ -100,7 +100,7 @@ TEST(Annotations, FillAnnotation) {
     test.map.addAnnotation(annotation);
     test.checkRendering("fill_annotation");
 
-    test.map.jumpTo(CameraOptions().withZoom(test.map.getMaxZoom()));
+    test.map.jumpTo(CameraOptions().withZoom(*test.map.getBounds().maxZoom));
     test.checkRendering("fill_annotation_max_zoom");
 }
 
@@ -481,11 +481,11 @@ TEST(Annotations, ChangeMaxZoom) {
     annotation.color = Color::red();
     annotation.width = { 5 };
 
-    test.map.setMaxZoom(6);
+    test.map.setBounds(BoundOptions().withMaxZoom(6));
     test.map.getStyle().loadJSON(util::read_file("test/fixtures/api/empty.json"));
     test.map.addAnnotation(annotation);
-    test.map.setMaxZoom(14);
-    test.map.jumpTo(CameraOptions().withZoom(test.map.getMaxZoom()));
+    test.map.setBounds(BoundOptions().withMaxZoom(14));
+    test.map.jumpTo(CameraOptions().withZoom(*test.map.getBounds().maxZoom));
     test.checkRendering("line_annotation_max_zoom");
 }
 
diff --git a/test/map/map.test.cpp b/test/map/map.test.cpp
index 0197202a9d..410a7e76af 100644
--- a/test/map/map.test.cpp
+++ b/test/map/map.test.cpp
@@ -282,6 +282,32 @@ TEST(Map, ProjectionMode) {
     EXPECT_EQ(*options.ySkew, 0.0);
 }
 
+TEST(Map, BoundOptions) {
+    MapTest<> test;
+
+    LatLngBounds llb = LatLngBounds::hull({-10, -10}, {10, 10});
+    test.map.setBounds(BoundOptions().withMinZoom(4).withMaxZoom(10).withLatLngBounds(llb));
+    auto bounds = test.map.getBounds();
+
+    EXPECT_EQ(*bounds.minZoom, 4);
+    EXPECT_EQ(*bounds.maxZoom, 10);
+    EXPECT_EQ(*bounds.bounds, llb);
+}
+
+TEST(Map, DefaultBoundOptions) {
+    MapTest<> test;
+
+    auto bounds = test.map.getBounds();
+
+    EXPECT_TRUE(bounds.minZoom);
+    EXPECT_TRUE(bounds.maxZoom);
+    EXPECT_TRUE(bounds.bounds);
+
+    EXPECT_EQ(*bounds.minZoom, util::MIN_ZOOM);
+    EXPECT_EQ(*bounds.maxZoom, util::DEFAULT_MAX_ZOOM);
+    EXPECT_EQ(*bounds.bounds, LatLngBounds::unbounded());
+}
+
 TEST(Map, SetStyleInvalidJSON) {
     Log::setObserver(std::make_unique<FixtureLogObserver>());