[core] Added padding option to CameraOptions

Moved EdgeInsets to geo.hpp so CameraOptions and Transform can refer to it. Added a padding option to CameraOptions that alters the frame of reference for the center option. Added optional padding parameters to LatLng getters and setters.

Working towards #2600.

4 files changed, 61 insertions, 8 deletions

diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index 50201ff949..f03915c953 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -172,7 +172,11 @@ void Map::moveBy(const PrecisionPoint& point, const Duration& duration) {
 }
 
 void Map::setLatLng(const LatLng& latLng, const Duration& duration) {
-    transform->setLatLng(latLng, duration);
+    setLatLng(latLng, EdgeInsets(), duration);
+}
+
+void Map::setLatLng(const LatLng& latLng, const EdgeInsets& padding, const Duration& duration) {
+    transform->setLatLng(latLng, padding, duration);
     update(Update::Repaint);
 }
 
@@ -181,8 +185,8 @@ void Map::setLatLng(const LatLng& latLng, const PrecisionPoint& point, const Dur
     update(Update::Repaint);
 }
 
-LatLng Map::getLatLng() const {
-    return transform->getLatLng();
+LatLng Map::getLatLng(const EdgeInsets& padding) const {
+    return transform->getLatLng(padding);
 }
 
 void Map::resetPosition() {
@@ -259,7 +263,7 @@ CameraOptions Map::cameraForLatLngs(const std::vector<LatLng>& latLngs, const Ed
     double scaleY = (getHeight() - padding.top - padding.bottom) / height;
     double minScale = ::fmin(scaleX, scaleY);
     double zoom = ::log2(getScale() * minScale);
-    zoom = ::fmax(::fmin(zoom, getMaxZoom()), getMinZoom());
+    zoom = util::clamp(zoom, getMinZoom(), getMaxZoom());
 
     // Calculate the center point of a virtual bounds that is extended in all directions by padding.
     PrecisionPoint paddedNEPixel = {
diff --git a/src/mbgl/map/transform.cpp b/src/mbgl/map/transform.cpp
index 98b0804482..7596d5d543 100644
--- a/src/mbgl/map/transform.cpp
+++ b/src/mbgl/map/transform.cpp
@@ -91,7 +91,12 @@ void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& anim
     }
     
     // Determine endpoints.
-    const LatLng startLatLng = getLatLng();
+    EdgeInsets padding;
+    if (camera.padding) {
+        padding = *camera.padding;
+    }
+    const LatLng startLatLng = getLatLng(padding);
+    padding.flip();
     const PrecisionPoint startPoint = {
         state.lngX(startLatLng.longitude),
         state.latY(startLatLng.latitude),
@@ -141,6 +146,10 @@ void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& anim
         if (pitch != startPitch) {
             state.pitch = util::interpolate(startPitch, pitch, t);
         }
+        
+        if (padding) {
+            state.moveLatLng(frameLatLng, padding.getCenter(state.width, state.height));
+        }
         return update;
     }, duration);
 }
@@ -164,7 +173,12 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
     }
     
     // Determine endpoints.
-    const LatLng startLatLng = getLatLng();
+    EdgeInsets padding;
+    if (camera.padding) {
+        padding = *camera.padding;
+    }
+    const LatLng startLatLng = getLatLng(padding);
+    padding.flip();
     const PrecisionPoint startPoint = {
         state.lngX(startLatLng.longitude),
         state.latY(startLatLng.latitude),
@@ -189,7 +203,8 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
     
     /// w₀: Initial visible span, measured in pixels at the initial scale.
     /// Known henceforth as a <i>screenful</i>.
-    double w0 = std::max(state.width, state.height);
+    double w0 = std::max(state.width - padding.left - padding.right,
+                         state.height - padding.top - padding.bottom);
     /// w₁: Final visible span, measured in pixels with respect to the initial
     /// scale.
     double w1 = w0 / state.zoomScale(zoom - startZoom);
@@ -304,6 +319,10 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
         if (pitch != startPitch) {
             state.pitch = util::interpolate(startPitch, pitch, k);
         }
+        
+        if (padding) {
+            state.moveLatLng(frameLatLng, padding.getCenter(state.width, state.height));
+        }
         return Update::Zoom;
     }, duration);
 }
@@ -340,12 +359,19 @@ void Transform::moveBy(const PrecisionPoint& offset, const Duration& duration) {
 }
 
 void Transform::setLatLng(const LatLng& latLng, const Duration& duration) {
+    setLatLng(latLng, EdgeInsets(), duration);
+}
+
+void Transform::setLatLng(const LatLng& latLng, const EdgeInsets& padding, const Duration& duration) {
     if (!latLng) {
         return;
     }
 
     CameraOptions camera;
     camera.center = latLng;
+    if (padding) {
+        camera.padding = padding;
+    }
     easeTo(camera, duration);
 }
 
@@ -381,6 +407,16 @@ void Transform::setLatLngZoom(const LatLng& latLng, double zoom, const Duration&
     easeTo(camera, duration);
 }
 
+LatLng Transform::getLatLng(const EdgeInsets& padding) const {
+    if (padding) {
+        EdgeInsets flippedPadding = padding;
+        flippedPadding.flip();
+        return state.pointToLatLng(flippedPadding.getCenter(state.width, state.height));
+    } else {
+        return state.getLatLng();
+    }
+}
+
 
 #pragma mark - Zoom
 
diff --git a/src/mbgl/map/transform.hpp b/src/mbgl/map/transform.hpp
index 6be0558f98..77c03e939d 100644
--- a/src/mbgl/map/transform.hpp
+++ b/src/mbgl/map/transform.hpp
@@ -43,9 +43,10 @@ public:
             top to bottom and from left to right. */
     void moveBy(const PrecisionPoint& offset, const Duration& = Duration::zero());
     void setLatLng(const LatLng&, const Duration& = Duration::zero());
+    void setLatLng(const LatLng&, const EdgeInsets&, const Duration& = Duration::zero());
     void setLatLng(const LatLng&, const PrecisionPoint&, const Duration& = Duration::zero());
     void setLatLngZoom(const LatLng&, double zoom, const Duration& = Duration::zero());
-    LatLng getLatLng() const { return state.getLatLng(); }
+    LatLng getLatLng(const EdgeInsets& = {}) const;
 
     // Zoom
 
diff --git a/src/mbgl/util/geo.cpp b/src/mbgl/util/geo.cpp
index e82f4afad2..a0ba44c4a9 100644
--- a/src/mbgl/util/geo.cpp
+++ b/src/mbgl/util/geo.cpp
@@ -28,4 +28,16 @@ LatLngBounds::LatLngBounds(const TileID& id)
       ne(TileID{ id.z, id.x + 1, id.y, id.sourceZ }) {
 }
 
+PrecisionPoint EdgeInsets::getCenter(uint16_t width, uint16_t height) const {
+    return {
+        (width - left - right) / 2.0f + left,
+        (height - top - bottom) / 2.0f + top,
+    };
+}
+
+void EdgeInsets::flip() {
+    std::swap(top, bottom);
+    std::swap(left, right);
+}
+
 } // end namespace mbgl