From f0c2f8eec023c7cddc6ac03e0ac18a295948a9f3 Mon Sep 17 00:00:00 2001
From: Dan Paulat <dpaulat@gmail.com>
Date: Sun, 6 Aug 2023 22:49:18 -0500
Subject: [PATCH] Correct text not following map rotation

---
 .../source/scwx/qt/map/placefile_layer.cpp    | 24 +++++++++++++++----
 wxdata/include/scwx/common/geographic.hpp     |  2 ++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/scwx-qt/source/scwx/qt/map/placefile_layer.cpp b/scwx-qt/source/scwx/qt/map/placefile_layer.cpp
index 37254a0d..2117932b 100644
--- a/scwx-qt/source/scwx/qt/map/placefile_layer.cpp
+++ b/scwx-qt/source/scwx/qt/map/placefile_layer.cpp
@@ -5,6 +5,7 @@
 #include <scwx/qt/manager/settings_manager.hpp>
 #include <scwx/qt/util/geographic_lib.hpp>
 #include <scwx/qt/util/maplibre.hpp>
+#include <scwx/common/geographic.hpp>
 #include <scwx/util/logger.hpp>
 
 #include <fmt/format.h>
@@ -59,6 +60,8 @@ public:
    std::uint32_t textId_ {};
    glm::vec2     mapScreenCoordLocation_ {};
    float         mapScale_ {1.0f};
+   float         mapBearingCos_ {1.0f};
+   float         mapBearingSin_ {0.0f};
    float         halfWidth_ {};
    float         halfHeight_ {};
    bool          thresholded_ {true};
@@ -149,12 +152,23 @@ void PlacefileLayer::Impl::RenderTextDrawItem(
                                       mapScreenCoordLocation_) *
                                      mapScale_;
 
+      // Rotate text according to map rotation
+      float rotatedX = screenCoordinates.x;
+      float rotatedY = screenCoordinates.y;
+      if (params.bearing != 0.0)
+      {
+         rotatedX = screenCoordinates.x * mapBearingCos_ -
+                    screenCoordinates.y * mapBearingSin_;
+         rotatedY = screenCoordinates.x * mapBearingSin_ +
+                    screenCoordinates.y * mapBearingCos_;
+      }
+
       RenderText(params,
                  di->text_,
                  di->hoverText_,
                  di->color_,
-                 screenCoordinates.x + di->x_ + halfWidth_,
-                 screenCoordinates.y + di->y_ + halfHeight_);
+                 rotatedX + di->x_ + halfWidth_,
+                 rotatedY + di->y_ + halfHeight_);
    }
 }
 
@@ -217,8 +231,10 @@ void PlacefileLayer::Render(
       {params.latitude, params.longitude});
    p->mapScale_ = std::pow(2.0, params.zoom) * mbgl::util::tileSize_D /
                   mbgl::util::DEGREES_MAX;
-   p->halfWidth_  = params.width * 0.5f;
-   p->halfHeight_ = params.height * 0.5f;
+   p->mapBearingCos_ = std::cosf(params.bearing * common::kDegreesToRadians);
+   p->mapBearingSin_ = std::sinf(params.bearing * common::kDegreesToRadians);
+   p->halfWidth_     = params.width * 0.5f;
+   p->halfHeight_    = params.height * 0.5f;
 
    // Get monospace font pointer
    std::size_t fontSize = 16;
diff --git a/wxdata/include/scwx/common/geographic.hpp b/wxdata/include/scwx/common/geographic.hpp
index 1318f43b..8945db17 100644
--- a/wxdata/include/scwx/common/geographic.hpp
+++ b/wxdata/include/scwx/common/geographic.hpp
@@ -11,6 +11,8 @@ namespace common
 constexpr double kMilesPerMeter      = 0.00062137119;
 constexpr double kKilometersPerMeter = 0.001;
 
+constexpr double kDegreesToRadians = 0.0174532925199432957692369055556;
+
 /**
  * @brief Coordinate type to hold latitude and longitude of a location.
  */