add more low level drawing functions

low_level_render.cpp

@@ -17,16 +17,64 @@
 #include "./fonts/zxpix_font.h"
 
 LowLevelRenderer::LowLevelRenderer(uint8_t* buffer, int width, int height)
-    : bit_buffer(buffer), V_WIDTH(width), V_HEIGHT(height), current_font(&font_acme_5_outlines) {}
+    : bit_buffer(buffer), V_WIDTH(width), V_HEIGHT(height), current_font(&font_acme_5_outlines),
+      clipping_enabled(false), clip_x(0), clip_y(0), clip_width(width), clip_height(height) {}
 
 void LowLevelRenderer::set_font(const unsigned char (*font)[96][6]) {
     current_font = font;
 }
 
+// Clipping functions
+void LowLevelRenderer::set_clip_rect(int x, int y, int width, int height) {
+    clip_x = x;
+    clip_y = y;
+    clip_width = width;
+    clip_height = height;
+    clipping_enabled = true;
+}
+
+void LowLevelRenderer::reset_clip_rect() {
+    clipping_enabled = false;
+    clip_x = 0;
+    clip_y = 0;
+    clip_width = V_WIDTH;
+    clip_height = V_HEIGHT;
+}
+
+bool LowLevelRenderer::is_clipping_enabled() const {
+    return clipping_enabled;
+}
+
+bool LowLevelRenderer::is_point_in_clip_rect(int x, int y) {
+    if (!clipping_enabled) return true;
+    return (x >= clip_x && x < clip_x + clip_width && 
+            y >= clip_y && y < clip_y + clip_height);
+}
+
+// Buffer operations
+void LowLevelRenderer::invert_buffer() {
+    int buffer_size = (V_WIDTH * V_HEIGHT + 7) / 8;  // Round up for bit buffer size
+    for (int i = 0; i < buffer_size; ++i) {
+        bit_buffer[i] = ~bit_buffer[i];  // Bitwise NOT to invert all bits
+    }
+}
+
+void LowLevelRenderer::clear_buffer() {
+    int buffer_size = (V_WIDTH * V_HEIGHT + 7) / 8;
+    for (int i = 0; i < buffer_size; ++i) {
+        bit_buffer[i] = 0;
+    }
+}
+
 void LowLevelRenderer::set_pixel(int x, int y, bool on)
 {
     if (x < 0 || x >= V_WIDTH || y < 0 || y >= V_HEIGHT)
         return;
+    
+    // Check clipping
+    if (!is_point_in_clip_rect(x, y))
+        return;
+        
     int bit_pos = y * V_WIDTH + x;
     if (on)
         bit_buffer[bit_pos / 8] |= (1 << (7 - (bit_pos % 8)));

low_level_render.h

@@ -33,9 +33,12 @@ private:
     int V_WIDTH;
     int V_HEIGHT;
     const unsigned char (*current_font)[96][6];
+    bool clipping_enabled;
+    int clip_x, clip_y, clip_width, clip_height;
     void draw_corner_arc(int center_x, int center_y, int radius, int quadrant, bool on);
     void fill_bottom_flat_triangle(int x1, int y1, int x2, int y2, int x3, int y3, bool on);
     void fill_top_flat_triangle(int x1, int y1, int x2, int y2, int x3, int y3, bool on);
+    bool is_point_in_clip_rect(int x, int y);
 
 public:
     LowLevelRenderer(uint8_t* buffer, int width, int height);
@@ -56,6 +59,16 @@ public:
     void draw_polygon(const std::vector<std::pair<int, int>>& points, bool on);
     void draw_filled_polygon(const std::vector<std::pair<int, int>>& points, bool on);
     void draw_arc(int center_x, int center_y, int radius, int start_angle, int end_angle, bool on);
+    
+    // Clipping functions
+    void set_clip_rect(int x, int y, int width, int height);
+    void reset_clip_rect();
+    bool is_clipping_enabled() const;
+    
+    // Buffer operations
+    void invert_buffer();
+    void clear_buffer();
+    
     void draw_circle(int x, int y, int radius, bool on);
     void draw_filled_circle(int x, int y, int radius, bool on);
     void draw_char_vcol(int x, int y, char c);

main.cpp

@@ -36,6 +36,7 @@ int main()
 
     sf::Clock clock;
     bool toggle = false;
+    bool inverted = false;
 
     while (window.isOpen())
     {
@@ -87,6 +88,14 @@ int main()
         {
             clock.restart();
             toggle = !toggle; // Change something every half second
+            
+            // Invert display every 4 seconds (8 cycles)
+            static int cycle_count = 0;
+            cycle_count++;
+            if (cycle_count % 8 == 0) {
+                renderer.invert_buffer();
+                inverted = !inverted;
+            }
 
             // Clear buffer
             for (int i = 0; i < sizeof(bit_buffer); i++)
@@ -131,9 +140,14 @@ int main()
             renderer.draw_line(10, 200, 90, 250, true);
             renderer.draw_line(110, 200, 190, 250, true);
             
+            // Demonstrate clipping - draw a circle that gets clipped
+            renderer.set_clip_rect(300, 200, 80, 60);  // Small rectangle in bottom-right
+            renderer.draw_filled_circle(340, 230, 40, true);  // Circle that extends outside clip rect
+            renderer.reset_clip_rect();  // Reset to full screen
+            
             // Text with different fonts
             renderer.set_font(&font_acme_5_outlines);
-            renderer.draw_string_scaled(10, 10, "Drawing Demo", 2);
+            renderer.draw_string_scaled(10, 10, inverted ? "INVERTED MODE" : "Drawing Demo", 2);
             
             renderer.set_font(&font_5x5);
             renderer.draw_string_scaled(10, 270, command_buffer, 1);