add: Simple widget system

frame/src/render/RenderTarget.cpp

@@ -7,15 +7,20 @@ namespace frame::render
 
     RenderTarget::RenderTarget(Size size)
         : image(size)
+        , root_size{0, 0, (int)size.width, (int)size.height}
     {
     }
 
     void RenderTarget::DrawPixel(Vector const& position, Color color)
     {
-        if(position.x < 0 || position.y < 0 || position.x >= image.getWidth()
-           || position.y >= image.getHeight())
+        auto current = getCurrentSize();
+
+        if(position.x < 0 || position.y < 0 || position.x >= current.width
+           || position.y >= current.height
+           || (position.x + current.left) >= root_size.width
+           || (position.y + current.top) >= root_size.height)
             return;
-        image.at(position.x, position.y) = color;
+        image.at(position.x + current.left, position.y + current.top) = color;
     }
 
     void RenderTarget::DrawLine(Vector const& start,
@@ -77,12 +82,16 @@ namespace frame::render
 
     void RenderTarget::DrawCircle(Vector const& center,
                                   int32_t radius,
+                                  int32_t line,
                                   Color color)
     {
         int32_t const r_2 = radius * radius;
         Vector pos{0, -radius};
 
-        DrawPointsMirrorCircle(center, pos, color);
+        for(auto i = 0; i < line; ++i)
+        {
+            DrawPointsMirrorCircle(center, {pos.x, pos.y + i}, color);
+        }
 
         while(pos.x <= radius / std::sqrt(2.f))
         {
@@ -102,7 +111,10 @@ namespace frame::render
                 E += 2 * pos.x - 2 * pos.y + 5;
             }
 
-            DrawPointsMirrorCircle(center, pos, color);
+            for(auto i = 0; i < line; ++i)
+            {
+                DrawPointsMirrorCircle(center, {pos.x, pos.y + i}, color);
+            }
         }
     }
 
@@ -199,7 +211,7 @@ namespace frame::render
 
         switch(alignVertical)
         {
-            case AlignVertical::TOP: start.y += lineSpacing_3 * 2; break;
+            case AlignVertical::TOP: start.y -= y_offset; break;
             case AlignVertical::CENTER:
                 start.y += rect.height / 2;
                 start.y += text_height / 2;
@@ -207,7 +219,7 @@ namespace frame::render
                 break;
             case AlignVertical::BOTTOM:
                 start.y += rect.height;
-                start.y += text_height + y_offset;
+                start.y -= text_height + y_offset;
                 break;
         }
 
@@ -249,6 +261,30 @@ namespace frame::render
         image.Clear(color);
     }
 
+    Rect RenderTarget::getCurrentSize() const
+    {
+        if(Scissor.size() == 0)
+        {
+            return root_size;
+        }
+        return Scissor.top();
+    }
+
+    void RenderTarget::pushViewport(Rect rect)
+    {
+        auto current = getCurrentSize();
+
+        Scissor.push({current.top + rect.top,
+                      current.left + rect.left,
+                      rect.width,
+                      rect.height});
+    }
+
+    void RenderTarget::popViewport()
+    {
+        Scissor.pop();
+    }
+
     void RenderTarget::DrawPointsMirrorCircle(Vector const& center,
                                               Vector const& pos,
                                               Color color)