Merge pull request #976 from MihailRis/screenshot-function

add gui.screenshot function

doc/en/scripting/builtins/libgui.md

@@ -61,6 +61,12 @@ gui.set_active_frame(
     -- Used for custom projection (e.g., in 3D)
     [optional] cursorLocator: function() -> number, number
 )
+
+-- Creates a screenshot of a frame as a Canvas object if the frame ID is specified, or the entire window if nil.
+gui.screenshot(
+    -- ID of the frame created via gui.create_frame
+    [optional] frameId: str
+) -> Canvas | nil
 ```
 
 ## Markup

doc/ru/scripting/builtins/libgui.md

@@ -69,6 +69,12 @@ gui.set_active_frame(
     -- Используется для пользовательской проекции (например в 3D)
     [опционально] cursorLocator: function() -> number, number
 )
+
+-- Создаёт снимок фрейма в виде объекта Canvas если указан id фрейма, или всего окна, в случае nil.
+gui.screenshot(
+    -- id фрейма, созданного через gui.create_frame
+    [опционально] frameId: str
+) -> Canvas | nil
 ```
 
 ## Разметка

src/graphics/core/Framebuffer.cpp

@@ -117,6 +117,13 @@ std::shared_ptr<Texture> Framebuffer::getSharedTexture() const {
     return texture;
 }
 
+std::unique_ptr<ImageData> Framebuffer::readData() const {
+    if (!texture) {
+        return nullptr;
+    }
+    return texture->readData();
+}
+
 uint Framebuffer::getWidth() const {
     return width;
 }

src/graphics/core/Framebuffer.hpp

@@ -6,6 +6,7 @@
 #include <memory>
 
 class Texture;
+class ImageData;
 
 class Framebuffer : public Bindable {
     uint fbo;
@@ -36,6 +37,8 @@ public:
 
     std::shared_ptr<Texture> getSharedTexture() const;
 
+    std::unique_ptr<ImageData> readData() const;
+
     /// @brief Get framebuffer width
     uint getWidth() const;
     /// @brief Get framebuffer height

src/graphics/ui/GUI.cpp

@@ -378,6 +378,14 @@ std::shared_ptr<gui::Frame> GUI::getActiveFrame() const {
     return activeFrame;
 }
 
+std::shared_ptr<gui::Frame> GUI::getFrame(const std::string& id) {
+    const auto& found = frames.find(id);
+    if (found == frames.end()) {
+        return nullptr;
+    }
+    return found->second;
+}
+
 void GUI::remove(UINode* node) noexcept {
     container->remove(node);
 }

src/graphics/ui/GUI.hpp

@@ -137,6 +137,8 @@ namespace gui {
 
         std::shared_ptr<Frame> getActiveFrame() const;
 
+        std::shared_ptr<Frame> getFrame(const std::string& id);
+
         /// @brief Remove node from the main container
         void remove(UINode* node) noexcept;
 

src/graphics/ui/elements/Frame.cpp

@@ -66,3 +66,10 @@ const std::string& gui::Frame::getOutputTexture() const {
 const std::string& gui::Frame::getFrameId() const {
     return frameId;
 }
+
+std::unique_ptr<ImageData> gui::Frame::takeScreenshot() const {
+    if (fbo == nullptr) {
+        return nullptr;
+    }
+    return fbo->readData();
+}

src/graphics/ui/elements/Frame.hpp

@@ -4,6 +4,7 @@
 
 class Framebuffer;
 class UiDocument;
+class ImageData;
 
 namespace gui {
     class Frame final : public Container {
@@ -18,6 +19,8 @@ namespace gui {
         const std::string& getOutputTexture() const;
 
         const std::string& getFrameId() const;
+
+        std::unique_ptr<ImageData> takeScreenshot() const;
     private:
         std::string frameId;
         std::unique_ptr<Framebuffer> fbo;

src/logic/scripting/lua/libs/libgui.cpp

@@ -25,6 +25,7 @@
 #include "items/Inventories.hpp"
 #include "util/stringutil.hpp"
 #include "world/Level.hpp"
+#include "window/Window.hpp"
 #include "../usertypes/lua_type_canvas.hpp"
 
 using namespace gui;
@@ -1218,7 +1219,26 @@ static int l_get_active_frame(lua::State* L) {
     return lua::pushstring(L, frame->getId());
 }
 
+static int l_screenshot(lua::State* L) {
+    if (engine->isHeadless()) {
+        return 0;
+    }
+    std::unique_ptr<ImageData> image;
+    if (lua::isstring(L, 1)) {
+        auto& gui = engine->getGUI();
+        auto frame = gui.getFrame(lua::require_string(L, 1));
+        if (frame == nullptr) {
+            return 0;
+        }
+        image = frame->takeScreenshot();
+    } else {
+        image = engine->getWindow().takeScreenshot();
+    }
+    return lua::newuserdata<lua::LuaCanvas>(L, nullptr, std::move(image));
+}
+
 const luaL_Reg guilib[] = {
+    {"screenshot", lua::wrap<l_screenshot>},
     {"get_viewport", lua::wrap<l_gui_getviewport>},
     {"getattr", lua::wrap<l_gui_getattr>},
     {"setattr", lua::wrap<l_gui_setattr>},