From fae9faab06a6fa800eee890f400035fb8c6a2eb9 Mon Sep 17 00:00:00 2001
From: Ivo van Dongen <info@ivovandongen.nl>
Date: Tue, 22 Aug 2017 16:32:09 +0300
Subject: [PATCH] [default] map snapshotter

---
 platform/default/mbgl/map/map_snapshotter.cpp | 76 +++++++++++++++++++
 platform/default/mbgl/map/map_snapshotter.hpp | 40 ++++++++++
 2 files changed, 116 insertions(+)
 create mode 100644 platform/default/mbgl/map/map_snapshotter.cpp
 create mode 100644 platform/default/mbgl/map/map_snapshotter.hpp

diff --git a/platform/default/mbgl/map/map_snapshotter.cpp b/platform/default/mbgl/map/map_snapshotter.cpp
new file mode 100644
index 000000000..95c46344f
--- /dev/null
+++ b/platform/default/mbgl/map/map_snapshotter.cpp
@@ -0,0 +1,76 @@
+#include <mbgl/map/map_snapshotter.hpp>
+
+#include <mbgl/actor/actor_ref.hpp>
+#include <mbgl/gl/headless_frontend.hpp>
+#include <mbgl/map/map.hpp>
+#include <mbgl/storage/file_source.hpp>
+#include <mbgl/style/style.hpp>
+#include <mbgl/util/event.hpp>
+
+namespace mbgl {
+
+class MapSnapshotter::Impl {
+public:
+    Impl(FileSource&,
+         Scheduler&,
+         const std::string& styleURL,
+         const Size&,
+         const float pixelRatio,
+         const CameraOptions&,
+         const optional<LatLngBounds> region,
+         const optional<std::string> programCacheDir);
+
+    void snapshot(ActorRef<MapSnapshotter::Callback>);
+
+private:
+    HeadlessFrontend frontend;
+    Map map;
+};
+
+MapSnapshotter::Impl::Impl(FileSource& fileSource,
+           Scheduler& scheduler,
+           const std::string& styleURL,
+           const Size& size,
+           const float pixelRatio,
+           const CameraOptions& cameraOptions,
+           const optional<LatLngBounds> region,
+           const optional<std::string> programCacheDir)
+    : frontend(size, pixelRatio, fileSource, scheduler, programCacheDir)
+    , map(frontend, MapObserver::nullObserver(), size, pixelRatio, fileSource, scheduler, MapMode::Still) {
+
+    map.getStyle().loadURL(styleURL);
+
+    map.jumpTo(cameraOptions);
+
+    // Set region, if specified
+    if (region) {
+        mbgl::EdgeInsets insets = { 0, 0, 0, 0 };
+        std::vector<LatLng> latLngs = { region->southwest(), region->northeast() };
+        map.jumpTo(map.cameraForLatLngs(latLngs, insets));
+    }
+}
+
+void MapSnapshotter::Impl::snapshot(ActorRef<MapSnapshotter::Callback> callback) {
+    map.renderStill([this, callback = std::move(callback)] (std::exception_ptr error) mutable {
+        callback.invoke(&MapSnapshotter::Callback::operator(), error, error ? PremultipliedImage() : frontend.readStillImage());
+    });
+}
+
+MapSnapshotter::MapSnapshotter(FileSource& fileSource,
+                               Scheduler& scheduler,
+                               const std::string& styleURL,
+                               const Size& size,
+                               const float pixelRatio,
+                               const CameraOptions& cameraOptions,
+                               const optional<LatLngBounds> region,
+                               const optional<std::string> programCacheDir)
+   : impl(std::make_unique<util::Thread<MapSnapshotter::Impl>>("Map Snapshotter", fileSource, scheduler, styleURL, size, pixelRatio, cameraOptions, region, programCacheDir)) {
+}
+
+MapSnapshotter::~MapSnapshotter() = default;
+
+void MapSnapshotter::snapshot(ActorRef<MapSnapshotter::Callback> callback) {
+   impl->actor().invoke(&Impl::snapshot, std::move(callback));
+}
+
+} // namespace mbgl
diff --git a/platform/default/mbgl/map/map_snapshotter.hpp b/platform/default/mbgl/map/map_snapshotter.hpp
new file mode 100644
index 000000000..0afa848fd
--- /dev/null
+++ b/platform/default/mbgl/map/map_snapshotter.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <mbgl/util/image.hpp>
+#include <mbgl/util/thread.hpp>
+#include <mbgl/util/optional.hpp>
+
+#include <exception>
+#include <string>
+#include <functional>
+
+namespace mbgl {
+
+template<class> class ActorRef;
+struct CameraOptions;
+class FileSource;
+class Size;
+class LatLngBounds;
+
+class MapSnapshotter {
+public:
+    MapSnapshotter(FileSource& fileSource,
+                   Scheduler& scheduler,
+                   const std::string& styleURL,
+                   const Size&,
+                   const float pixelRatio,
+                   const CameraOptions&,
+                   const optional<LatLngBounds> region,
+                   const optional<std::string> cacheDir = {});
+
+    ~MapSnapshotter();
+
+    using Callback = std::function<void (std::exception_ptr, PremultipliedImage)>;
+    void snapshot(ActorRef<Callback>);
+
+private:
+    class Impl;
+    std::unique_ptr<util::Thread<Impl>> impl;
+};
+
+} // namespace mbgl