Basic dda testing

exercise2/src/dda_line_tool.cpp

@@ -6,16 +6,14 @@
 #include "dda_line_tool.h"
 #include <algorithm>
 
+#include <iostream>
 
 // Initialize the tool and store a reference of a canvas_buffer
-dda_line_tool::dda_line_tool(canvas_buffer& canvas): tool_base(canvas)
+dda_line_tool::dda_line_tool(canvas_buffer &canvas) : tool_base(canvas)
 {
 	shape = TS_LINE;
 }
 
-
-
-
 // Draw a line from (x0, y0) to (x1, y1)
 void dda_line_tool::draw(int x0, int y0, int x1, int y1)
 {
@@ -29,19 +27,90 @@ void dda_line_tool::draw(int x0, int y0, int x1, int y1)
 	Aufgabe 3.1.1. Implementieren Sie den DDA-Algorithmus um eine Linie von
 	               (x0, y0) nach (x1, y1) zu rastern. Verwenden Sie
 				   "canvas.set_pixel(x, y)" um einen Pixel zu setzen, wobei
-				   "x" und "y" den gewünschten Pixelpositionen entsprechen.
+				   "x" und "y" den gew<EFBFBD>nschten Pixelpositionen entsprechen.
 				   Diese Methode behandelt auch Randverletzungen. Stellen Sie zunaechst
 				   den Standardfall her. Falls Sie den Wert zweier Variablen vertauschen
-				   muessen koennen Sie dafür die Methode "std::swap(a, b)" verwenden.
+				   muessen koennen Sie daf<EFBFBD>r die Methode "std::swap(a, b)" verwenden.
    	*************/
+
+	/*
+	int tmp;
+	// check all different cases
+
+	// mirror on x-achsis (y -> -y)
+	if (x0 < x1 && y0 > y1)
+	{
+		y0 = -y0;
+		y1 = -y1;
+
+		float y = static_cast<float>(y0);
+		float m = static_cast<float>(y1 - y0) / static_cast<float>(x1 - x0);
+
+		// '<=' - because we need to include x1 as end location
+		for (int x = x0; x <= x1; x++)
+		{
+			int i_y = static_cast<int>(y + 0.5f);
+			// (y -> -y)
+			canvas.set_pixel(x, -i_y);
+			y += m;
+		}
+	}
+	// rotate by 90° (x <-> -y)
+	else if (x0 > x1 && y0 < y1)
+	{
+		tmp = x0;
+		x0 = -y0;
+		y0 = tmp;
+
+		tmp = x1;
+		x1 = -y1;
+		y1 = tmp;
+
+		float y = static_cast<float>(y0);
+		float m = static_cast<float>(y1 - y0) / static_cast<float>(x1 - x0);
+
+		// '<=' - because we need to include x1 as end location
+		for (int x = x0; x <= x1; x++)
+		{
+			int i_y = static_cast<int>(y + 0.5f);
+			// (x <-> -y)
+			canvas.set_pixel(-i_y, x);
+			y += m;
+		}
+	}
+	// mirror on main diagonal (x <-> y)
+	else if (x)
+	{
+
+	}
+	// standard
+	else
+	{
+	*/
+
+	if (x0 > x1)
+	{
+		std::swap(x0, x1);
+		std::swap(y0, y1);
+	}
+
+	float m = static_cast<float>(y1 - y0) / static_cast<float>(x1 - x0);
+
+	std::cout << "anstieg " << m << std::endl;
+
+	float y = static_cast<float>(y0);
+	for (int x = x0; x < x1; x++)
+	{
+		canvas.set_pixel(x, static_cast<int>(y + 0.5f));
+		y += m;
+	}
+
+	//}
 }
 
-
-
-
 // Put debug output into the stream "stream" to be displayed in the
 // main window
-void dda_line_tool::set_text(std::stringstream& stream)
+void dda_line_tool::set_text(std::stringstream &stream)
 {
-	stream<<"Tool: DDA-Line (click and drag mouse to draw)";
+	stream << "Tool: DDA-Line (click and drag mouse to draw)";
 }