Fix position math and scaling

Author: RedTTG

rm_lines/headers/advanced/math.h

@@ -105,6 +105,11 @@ namespace AdvancedMath {
             y *= other.y;
         }
 
+        void operator*=(const float &other) {
+            x *= other;
+            y *= other;
+        }
+
         void operator/=(const Vector &other) {
             x /= other.x;
             y /= other.y;

rm_lines/src/renderer/renderer.cpp

@@ -241,21 +241,7 @@ void Renderer::getFrame(uint32_t *data, const size_t dataSize, Vector position,
     const auto lineBuf = &stroker.raster.raster.fill.lineBuffer;
     const auto scale = bufferSize / frameSize;
 
-    // Align the position to scale properly to the center of the requested frame
-    // The scale is automatically calculated by the provided bufferSize and frameSize
-    // In this case the frameSize could be let's say smaller but the buffer is larger and the scale is 2
-    // To compensate for this we need to align the position to the center of the frame
-    // If this isn't done the scaling will look as if from the top left corner
-
-    // Align to 0, 0
-    position += frameSize / 2;
-    position -= bufferSize / 2;
-
-    // Align to the scale
-    position -= Vector(
-        frameSize.x * (scale.x - 1), // Scale of 1 means no change, so we subtract 1 from the scale
-        frameSize.y * (scale.y - 1)
-    ) / 2;
+    position *= -1; // It's technically an offset
 
     stroker.joinStyle = JoinStyle::RoundJoin;
     stroker.raster.raster.fill.stroker = &stroker;

tests/draw_test.py

@@ -39,9 +39,11 @@
             image.save(output_path, 'PNG')
 
         rect = Rect(0, 0, *paper_size)
-        combined = Image.new('RGB', (paper_size[0] * 3, paper_size[1]))
+        tophalf = Rect(0, 0, paper_size[0] // 2, paper_size[1] // 2)
+        bottomhalf = Rect(paper_size[0] // 2, paper_size[1] // 2, paper_size[0] // 2, paper_size[1] // 2)
+        combined = Image.new('RGB', (paper_size[0] * 4, paper_size[1]))
         print("Creating a scaling combined frame test...")
-        for i, rect in enumerate((rect.scale_by(2, 2), rect, rect.scale_by(0.5, 0.5))):
+        for i, rect in enumerate((rect, tophalf, bottomhalf, rect.scale_by(2, 2))):
             lib.getFrame(renderer_id, buffer, buffer_size * 4, *rect.topleft, *rect.size, *paper_size, True)
             raw_frame = bytes(buffer)
             image = Image.frombytes('RGBA', paper_size, raw_frame, 'raw', 'RGBA')

tests/tests_base.py

@@ -80,3 +80,4 @@ def check_decode(raw: bytes, name: str):
 lib.setLogger(python_logger)
 lib.setErrorLogger(python_error_logger)
 lib.setDebugLogger(python_debug_logger)
+# lib.setDebugMode(True)