feat: autoresize (extend/shrink) canvas element

src/graphics/core/ImageData.cpp

@@ -470,6 +470,32 @@ void ImageData::addColor(const ImageData& other, int multiplier) {
     }
 }
 
+void ImageData::extend(int newWidth, int newHeight) {
+    size_t comps;
+    switch (format) {
+        case ImageFormat::rgb888: comps = 3; break;
+        case ImageFormat::rgba8888: comps = 4; break;
+        default:
+            throw std::runtime_error("only unsigned byte formats supported");    
+    }
+    auto newData = std::make_unique<ubyte[]>(newWidth * newHeight * comps);
+    for (uint y = 0; y < newHeight; y++) {
+        for (uint x = 0; x < newWidth; x++) {
+            for (size_t c = 0; c < comps; c++) {
+                if (x < width && y < height) {
+                    newData[(y * newWidth + x) * comps + c] =
+                        data[(y * width + x) * comps + c];
+                } else {
+                    newData[(y * newWidth + x) * comps + c] = 0;
+                }
+            }
+        }
+    }
+    data = std::move(newData);
+    width = newWidth;
+    height = newHeight;
+}
+
 void ImageData::addColor(const glm::ivec4& color, int multiplier) {
     uint comps;
     switch (format) {

src/graphics/core/ImageData.hpp

@@ -36,6 +36,7 @@ public:
     void mulColor(const ImageData& other);
     void addColor(const glm::ivec4& color, int multiplier);
     void addColor(const ImageData& other, int multiplier);
+    void extend(int newWidth, int newHeight);
 
     std::unique_ptr<ImageData> cropped(int x, int y, int width, int height) const;
 

src/graphics/core/Texture.cpp

@@ -44,10 +44,10 @@ void Texture::unbind() const {
 void Texture::reload(const ImageData& image) {
     width = image.getWidth();
     height = image.getHeight();
-    reload(image.getData());
+    reload(image.getData(), width, height);
 }
 
-void Texture::reload(const ubyte* data) {
+void Texture::reload(const ubyte* data, uint width, uint height) {
     glBindTexture(GL_TEXTURE_2D, id);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0,
         GL_RGBA, GL_UNSIGNED_BYTE, static_cast<const GLvoid*>(data));

src/graphics/core/Texture.hpp

@@ -18,7 +18,7 @@ public:
 
     virtual void bind() const;
     virtual void unbind() const;
-    void reload(const ubyte* data);
+    void reload(const ubyte* data, uint w, uint h);
     void reloadPartial(const ImageData& image, uint x, uint y, uint w, uint h);
 
     void setNearestFilter();

src/graphics/ui/elements/Canvas.cpp

@@ -4,11 +4,11 @@
 #include "graphics/core/DrawContext.hpp"
 #include "graphics/core/Texture.hpp"
 
-gui::Canvas::Canvas(GUI& gui, ImageFormat inFormat, glm::uvec2 inSize)
-    : UINode(gui, inSize) {
-    auto data = std::make_shared<ImageData>(inFormat, inSize.x, inSize.y);
-    mTexture = Texture::from(data.get());
-    mData = std::move(data);
+gui::Canvas::Canvas(GUI& gui, ImageFormat format, glm::uvec2 size)
+    : UINode(gui, size) {
+    auto data = std::make_shared<ImageData>(format, size.x, size.y);
+    texture = Texture::from(data.get());
+    this->data = std::move(data);
 }
 
 void gui::Canvas::draw(const DrawContext& pctx, const Assets& assets) {
@@ -16,6 +16,12 @@ void gui::Canvas::draw(const DrawContext& pctx, const Assets& assets) {
     auto col = calcColor();
 
     auto batch = pctx.getBatch2D();
-    batch->texture(mTexture.get());
+    batch->texture(texture.get());
     batch->rect(pos.x, pos.y, size.x, size.y, 0, 0, 0, {}, false, false, col);
 }
+
+void gui::Canvas::setSize(glm::vec2 size) {
+    UINode::setSize(size);
+    data->extend(size.x, size.y);
+    texture->reload(*data);
+}

src/graphics/ui/elements/Canvas.hpp

@@ -9,21 +9,23 @@ class Texture;
 namespace gui {
     class Canvas final : public UINode {
     public:
-        explicit Canvas(GUI& gui, ImageFormat inFormat, glm::uvec2 inSize);
+        explicit Canvas(GUI& gui, ImageFormat format, glm::uvec2 size);
 
         ~Canvas() override = default;
 
         void draw(const DrawContext& pctx, const Assets& assets) override;
 
-        [[nodiscard]] auto texture() const {
-            return mTexture;
+        void setSize(glm::vec2 size) override;
+
+        [[nodiscard]] auto getTexture() const {
+            return texture;
         }
 
-        [[nodiscard]] auto data() const {
-            return mData;
+        [[nodiscard]] auto getData() const {
+            return data;
         }
     private:
-        std::shared_ptr<::Texture> mTexture;
-        std::shared_ptr<ImageData> mData;
+        std::shared_ptr<::Texture> texture;
+        std::shared_ptr<ImageData> data;
     };
 }

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

@@ -380,7 +380,7 @@ static int p_get_region(UINode* node, lua::State* L) {
 
 static int p_get_data(UINode* node, lua::State* L) {
     if (auto canvas = dynamic_cast<Canvas*>(node)) {
-        return lua::newuserdata<lua::LuaCanvas>(L, canvas->texture(), canvas->data());
+        return lua::newuserdata<lua::LuaCanvas>(L, canvas->getTexture(), canvas->getData());
     }
     return 0;
 }