[从头学数学] 第121节 平面直角坐标系 小结与复习题

剧情提要：
[机器小伟]在[工程师阿伟]的陪同下进入了筑基初期的修炼，
这次要修炼的目标是[平面直角坐标系 小结与复习题]。

正剧开始：

星历2016年03月04日 12:11:27, 银河系厄尔斯星球中华帝国江南行省。
[工程师阿伟]正在和[机器小伟]一起研究[平面直角坐标系 小结与复习题]。

本次修炼中的习题解答代码，至少有一半是不需要的，主要是为了方便，就没有删除。

<span style="font-size:18px;">//题1
function myDraw() {   
      
    var config = new PlotConfiguration();      
    config.init();      
    config.setPreference();  		
    
	var r = 31;
	
	var image = new Image();
	image.src = './1.jpg';
	
	image.onload = function() {
		plot.translate(300, 0);
		plot.drawImage(image);
		
		config.setSector(1,1,1,1);  
		config.graphPaper2D(0, 0, r);
		config.axis2D(0, 0, 180);  
		
		var array = [[2,3],[-2,3],[-2,-3],[2,-3]];	
		
		var len = array.length;
		if (len > 0) {
			var tmp = [].concat(array);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array);
			//shape.fillDraw(tmp, 'pink', r);
			shape.multiLineDraw(tmp, 'blue', r);
			var s = '['+array.join('], [')+']';
			var measure = plot.measureText(s);
			if (measure>600) {
				plot.fillText(s, -300, 150, 600);
			}
			else {
				plot.fillText(s, -measure/2, 150, measure);
			}
		}
	}
	
}
</span>

<span style="font-size:18px;">//题2
function myDraw() {   
      
    var config = new PlotConfiguration();      
    config.init();      
    config.setPreference();  		
    
	var r = 27;
	
	var image = new Image();
	image.src = './1.jpg';
	
	image.onload = function() {
		plot.translate(300-6*r, 0.9*r);
		plot.drawImage(image);
		
		config.setSector(1,1,1,1);  
		config.graphPaper2D(0, 0, r);
		config.axis2D(0, 0, 180);  
		
		var array = [];	
		
		var len = array.length;
		if (len > 0) {
			var tmp = [].concat(array);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array);
			//shape.fillDraw(tmp, 'pink', r);
			shape.multiLineDraw(tmp, 'blue', r);
			var s = '['+array.join('], [')+']';
			var measure = plot.measureText(s);
			if (measure>600) {
				plot.fillText(s, -300, 150, 600);
			}
			else {
				plot.fillText(s, -measure/2, 150, measure);
			}
		}
	}
	
}</span>

<span style="font-size:18px;">//题3
function myDraw() {   
      
    var config = new PlotConfiguration();      
    config.init();      
    config.setPreference();  		
    
	var r = 20;
	
	var image = new Image();
	image.src = './1.jpg';
	
	image.onload = function() {
		plot.translate(300, 0);
		plot.drawImage(image);
		
		config.setSector(1,1,1,1);  
		config.graphPaper2D(0, 0, r);
		config.axis2D(0, 0, 180);  
		
		var array = [[2, 0], [4,0],[2,2]];	
		var array2 = [[0,2],[0,4],[-2,2]];
		var array3 = [[-4,0],[-2,-2],[-2,0]];
		var array4 = [[0,-2],[2,-2],[0,-4]];
		
		var len = array.length;
		
		if (len > 0) {
			var tmp = [].concat(array);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array);
			shape.strokeDraw(tmp, 'blue', r);
			
			
			tmp = [].concat(array2);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array2);
			shape.strokeDraw(tmp, 'blue', r);
			
			
			tmp = [].concat(array3);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array3);
			shape.strokeDraw(tmp, 'blue', r);		

			tmp = [].concat(array4);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array4);
			shape.strokeDraw(tmp, 'blue', r);			
			
			/*
			var s = '['+array.join('], [')+']';
			var measure = plot.measureText(s);
			if (measure>600) {
				plot.fillText(s, -300, 150, 600);
			}
			else {
				plot.fillText(s, -measure/2, 150, measure);
			}*/
		}
	}
	
}
</span>

<span style="font-size:18px;">//题4
function myDraw() {   
      
    var config = new PlotConfiguration();      
    config.init();      
    config.setPreference();  		
    
	var r = 35;
	
	var image = new Image();
	image.src = './1.jpg';
	
	image.onload = function() {
		plot.translate(300-5.2*r, 0.9*r);
		plot.drawImage(image);
		
		config.setSector(1,1,1,1);  
		config.graphPaper2D(0, 0, r);
		config.axis2D(0, 0, 180);  
		
		var array = [[-100,200],[100,0],[200,100],[200,-200],[-100,-200],[0,-100]];	
		r/=100;
		
		var len = array.length;
		
		if (len > 0) {
			var tmp = [].concat(array);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array);
			shape.multiLineDraw(tmp, 'blue', r);
			
		
			
			
			var s = '['+array.join('], [')+']';
			var measure = plot.measureText(s);
			if (measure>600) {
				plot.fillText(s, -300, 150, 600);
			}
			else {
				plot.fillText(s, -measure/2, 150, measure);
			}
		}
	}
	
}
</span>

下面是这个村子的水井位置，中心点是村委会，比例尺是1:250。

<span style="font-size:18px;">//题8
function myDraw() {   
      
    var config = new PlotConfiguration();      
    config.init();      
    config.setPreference();  		
    
	var r = 20;
	
	var image = new Image();
	image.src = './1.jpg';
	
	image.onload = function() {
		plot.translate(300, 0);
		plot.drawImage(image);
		
		config.setSector(1,1,1,1);  
		config.graphPaper2D(0, 0, r);
		config.axis2D(0, 0, 180);  
		
		var array = [[0, 0],[1000, 1732],[-1500,0],[707,-707],[0,-900]];	
		r/=250;
		
		var len = array.length;
		
		if (len > 0) {
			var tmp = [].concat(array);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array);
			shape.multiLineDraw(tmp, 'blue', r);
			
		
			
			
			var s = '['+array.join('], [')+']';
			var measure = plot.measureText(s);
			if (measure>600) {
				plot.fillText(s, -300, 150, 600);
			}
			else {
				plot.fillText(s, -measure/2, 150, measure);
			}
		}
	}
	
}
</span>

<span style="font-size:18px;">//题10
function myDraw() {   
      
    var config = new PlotConfiguration();      
    config.init();      
    config.setPreference();  		
    
	var r = 40;
	
	var image = new Image();
	image.src = './1.jpg';
	
	image.onload = function() {
		plot.translate(300, 0);
		plot.drawImage(image);
		
		config.setSector(1,1,1,1);  
		config.graphPaper2D(0, 0, r);
		config.axis2D(0, 0, 180);  
		
		var array = [[1,1],[5,1],[3,3],[-3,3],[1,-2],[1,4],[3,2],[3,-2],[-1,-1],[-1,1]];	
		var lable = 'ABCDEFGHIJ';
		
		var len = array.length;
		
		for (var i = 0; i < len; i++) {
			plot.fillText(lable[i], array[i][0]*r, -array[i][1]*r-5, 20);
		}
		
		if (len > 0) {
			var tmp = [].concat(array);
			shape.pointDraw(tmp, 'red', r);
			tmp = [].concat(array);
			//shape.multiLineDraw(tmp, 'blue', r);
			
		
			
			
			var s = '['+array.join('], [')+']';
			var measure = plot.measureText(s);
			if (measure>600) {
				plot.fillText(s, -300, 150, 600);
			}
			else {
				plot.fillText(s, -measure/2, 150, measure);
			}
		}
	}
	
}</span>

本节到此结束，欲知后事如何，请看下回分解。