[core] Introduce Renderer::clearData() instead of keepRenderData map options

`Renderer::clearData()` is a better API than the removed `MapOptions::keepRenderData()`:
- gives more flexibility to the client
- similar to the existing `Renderer::reduceMemoryUse()`
- the `MapOptions::keepRenderData()` API implementation could not handle the raise condition, which
happened if the new still image request had come before all tiles from the previous requests were loaded.

Co-authored-by: Dane Springmeyer <dane@mapbox.com>

4 files changed, 6 insertions, 10 deletions

diff --git a/src/mbgl/renderer/render_orchestrator.cpp b/src/mbgl/renderer/render_orchestrator.cpp
index 985aac98b4..08338ff616 100644
--- a/src/mbgl/renderer/render_orchestrator.cpp
+++ b/src/mbgl/renderer/render_orchestrator.cpp
@@ -141,10 +141,6 @@ std::unique_ptr<RenderTree> RenderOrchestrator::createRenderTree(
     if (!isMapModeContinuous) {
         // Reset zoom history state.
         zoomHistory.first = true;
-        if (!updateParameters->keepRenderData && stillImageRequest != updateParameters->stillImageRequest) {
-            clearData();
-            stillImageRequest = updateParameters->stillImageRequest;
-        }
     }
 
     if (LayerManager::annotationsEnabled) {
diff --git a/src/mbgl/renderer/render_orchestrator.hpp b/src/mbgl/renderer/render_orchestrator.hpp
index 312b28fd56..7c1abfe1f4 100644
--- a/src/mbgl/renderer/render_orchestrator.hpp
+++ b/src/mbgl/renderer/render_orchestrator.hpp
@@ -75,11 +75,11 @@ public:
 
     void reduceMemoryUse();
     void dumpDebugLogs();
+    void clearData();
 
 private:
     bool isLoaded() const;
     bool hasTransitions(TimePoint) const;
-    void clearData();
 
     RenderSource* getRenderSource(const std::string& id) const;
 
@@ -127,7 +127,6 @@ private:
 
     const bool backgroundLayerAsColor;
     bool contextLost = false;
-    const void* stillImageRequest = nullptr;
 
     // Vectors with reserved capacity of layerImpls->size() to avoid reallocation
     // on each frame.
diff --git a/src/mbgl/renderer/renderer.cpp b/src/mbgl/renderer/renderer.cpp
index 5afbbbd47e..ac2f327a4e 100644
--- a/src/mbgl/renderer/renderer.cpp
+++ b/src/mbgl/renderer/renderer.cpp
@@ -131,4 +131,8 @@ void Renderer::reduceMemoryUse() {
     impl->orchestrator.reduceMemoryUse();
 }
 
+void Renderer::clearData() {
+    impl->orchestrator.clearData();
+}
+
 } // namespace mbgl
diff --git a/src/mbgl/renderer/update_parameters.hpp b/src/mbgl/renderer/update_parameters.hpp
index fbdebc4197..4336fa0972 100644
--- a/src/mbgl/renderer/update_parameters.hpp
+++ b/src/mbgl/renderer/update_parameters.hpp
@@ -41,12 +41,9 @@ public:
     const uint8_t prefetchZoomDelta;
     
     // For still image requests, render requested
-    const void* stillImageRequest;
+    const bool stillImageRequest;
 
     const bool crossSourceCollisions;
-
-    // If set, the render data from the previous render calls is kept.
-    const bool keepRenderData;
 };
 
 } // namespace mbgl