Add bresenham circle and rectangle

exercise2/include/bresenham_circle_tool.h

@@ -1,12 +1,12 @@
 //
-// This source code is property of the Computer Graphics and Visualization 
+// This source code is property of the Computer Graphics and Visualization
-// chair of the TU Dresden. Do not distribute in modified or unmodified form! 
+// chair of the TU Dresden. Do not distribute in modified or unmodified form!
 // Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
 //
 /*************************************************************************
 Bresenham-Circle tool.
 This class is inherited from "tool_base" to define a tool for drawing
-circles using the bresenham algorithm on a canvas_buffer. 
+circles using the bresenham algorithm on a canvas_buffer.
 Read the information in "tool_base.h" for more information.
 *************************************************************************/
 #pragma once
@@ -14,7 +14,7 @@ Read the information in "tool_base.h" for more information.
 // provides the declaration of the super class tool_base
 #include "tool_base.h"
 
-class bresenham_circle_tool: public tool_base
+class bresenham_circle_tool : public tool_base
 {
 public:
 	// Initialize the tool and store a reference of a canvas_buffer
@@ -25,5 +25,8 @@ public:
 
 	// Put debug output into the stream "stream" to be displayed in the
 	// main window
-	void set_text(std::stringstream& stream);
+	void set_text(std::stringstream &stream);
+
+private:
+	void draw_circle(int xc, int yc, int x, int y);
 };

exercise2/src/bresenham_circle_tool.cpp

@@ -1,6 +1,6 @@
 //
-// This source code is property of the Computer Graphics and Visualization 
+// This source code is property of the Computer Graphics and Visualization
-// chair of the TU Dresden. Do not distribute in modified or unmodified form! 
+// chair of the TU Dresden. Do not distribute in modified or unmodified form!
 // Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
 //
 #include "bresenham_circle_tool.h"
@@ -8,19 +8,29 @@
 #include <math.h>
 
 // Initialize the tool and store a reference of a canvas_buffer
-bresenham_circle_tool::bresenham_circle_tool(canvas_buffer& canvas): tool_base(canvas)
+bresenham_circle_tool::bresenham_circle_tool(canvas_buffer &canvas) : tool_base(canvas)
 {
 	// This tool draws circles!
 	shape = TS_CIRCLE;
 }
 
-
+void bresenham_circle_tool::draw_circle(int xc, int yc, int x, int y)
+{
+	canvas.set_pixel(xc + x, yc + y);
+	canvas.set_pixel(xc - x, yc + y);
+	canvas.set_pixel(xc + x, yc - y);
+	canvas.set_pixel(xc - x, yc - y);
+	canvas.set_pixel(xc + y, yc + x);
+	canvas.set_pixel(xc - y, yc + x);
+	canvas.set_pixel(xc + y, yc - x);
+	canvas.set_pixel(xc - y, yc - x);
+}
 
 // Draw a circle with center (x0, y0) and (x1, y1) on the circle
 void bresenham_circle_tool::draw(int x0, int y0, int x1, int y1)
 {
 	// Calculate the radius
-	int r = static_cast<int>(sqrt(static_cast<double>((x0-x1)*(x0-x1) + (y0-y1)*(y0-y1))));
+	int r = static_cast<int>(sqrt(static_cast<double>((x0 - x1) * (x0 - x1) + (y0 - y1) * (y0 - y1))));
 
 	/************
 	Additional task: Implement circle rasterization using the bresenham algorithm.
@@ -31,13 +41,39 @@ void bresenham_circle_tool::draw(int x0, int y0, int x1, int y1)
 					 (x0, y0) und einen Radius von "r" haben.
 	*************/
 
+	int x = 0;
+	int y = r;
+	int d = 3 - 2 * r;
+
+	draw_circle(x0, y0, x, y);
+
+	while (y >= x)
+	{
+		// for each pixel we will
+		// draw all eight pixels
+
+		x++;
+
+		// check for decision parameter
+		// and correspondingly
+		// update d, x, y
+		if (d > 0)
+		{
+			y--;
+			d = d + 4 * (x - y) + 10;
+		}
+		else
+		{
+			d = d + 4 * x + 6;
+		}
+
+		draw_circle(x0, y0, x, y);
+	}
 }
 
-
-
 // Put debug output into the stream "stream" to be displayed in the
 // main window
-void bresenham_circle_tool::set_text(std::stringstream& stream)
+void bresenham_circle_tool::set_text(std::stringstream &stream)
 {
-	stream<<"Tool: Bresenham-Circle (click and drag mouse to draw)";
+	stream << "Tool: Bresenham-Circle (click and drag mouse to draw)";
 }

exercise2/src/rectangle_tool.cpp

@@ -1,20 +1,17 @@
 //
-// This source code is property of the Computer Graphics and Visualization 
+// This source code is property of the Computer Graphics and Visualization
-// chair of the TU Dresden. Do not distribute in modified or unmodified form! 
+// chair of the TU Dresden. Do not distribute in modified or unmodified form!
 // Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
 //
 #include "rectangle_tool.h"
 #include <algorithm>
 
-
 // Initialize the tool and store a reference of a canvas_buffer
-rectangle_tool::rectangle_tool(canvas_buffer& canvas): tool_base(canvas)
+rectangle_tool::rectangle_tool(canvas_buffer &canvas) : tool_base(canvas)
 {
 	shape = TS_BOX;
 }
 
-
-
 // Draw a box from (x0, y0) to (x1, y1)
 void rectangle_tool::draw(int x0, int y0, int x1, int y1)
 {
@@ -24,13 +21,29 @@ void rectangle_tool::draw(int x0, int y0, int x1, int y1)
     Zusatzaufgabe:   Implementieren Sie die Rasterisierung eines
 	                 Rechtecks, das von (x0, y0) nach (x1, y1) geht.
 	*************/
+
+	if (x0 > x1)
+	{
+		std::swap(x0, x1);
+	}
+
+	if (y0 > y1)
+	{
+		std::swap(y0, y1);
+	}
+
+	for (int x = x0; x <= x1; x++)
+	{
+		for (int y = y0; y <= y1; y++)
+		{
+			canvas.set_pixel(x, y);
+		}
+	}
 }
 
-
-
 // Put debug output into the stream "stream" to be displayed in the
 // main window
-void rectangle_tool::set_text(std::stringstream& stream)
+void rectangle_tool::set_text(std::stringstream &stream)
 {
-	stream<<"Tool: Rectangle (click and drag mouse to draw)";
+	stream << "Tool: Rectangle (click and drag mouse to draw)";
 }