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)));