【JavaScript】Duke大学 程序设计与Web

基本运算

var x = 4;
var y = 5;
var z = x + x * y
print(z)

结果如下
24

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图片处理

var image = new SimpleImage("drewRobert.png");
print(image)
print(image.getWidth(), image.getHeight())
print(image.getPixel(0,0))
print(image.getRed(0,0))
print(image.getGreen(0,0))
print(image.getBlue(0,0))

效果如下

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自制函数

function square(x){
	var ans = x*x;
	return ans;
}

print(square(4))

结果如下
16

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创建图片

创建一个黄色的200*200Pixel图片

var img = new SimpleImage(200,200);
for (var pixel of img.values()){
    pixel.setRed(255);
    pixel.setGreen(255);
    pixel.setBlue(0);
}

print(img);

效果如下

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更改图片样式

1. Turn the chapel red
将所有pixel的红色置为最深。

var image = new SimpleImage("chapel.png");
for(var pixel of image.values()){
    pixel.setRed(255);
}

print(image);

效果

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2. Remove all the red
将所有pixel的红色置为无。

var image = new SimpleImage("chapel.png");
for(var pixel of image.values()){
    pixel.setRed(0);
}

print(image);

效果

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3. Turn the eggs less red
将图中pixel所有红色值大于70的设置为70。

var image = new SimpleImage("eastereggs.jpg");
for(var pixel of image.values()){
    if(pixel.getRed()>70){
        pixel.setRed(70);
    }
}

print(image);

效果

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4. 将图片中最后10行置为黑色

var image = new SimpleImage("astrachan.jpg");
for(var pixel of image.values()){
    if(pixel.getY() >= (image.getHeight()-10)){
        pixel.setRed(0);
        pixel.setGreen(0);
        pixel.setBlue(0);
    }
}
print(image);

效果

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6. 左上角50*50设置为绿色

var image = new SimpleImage("chapel.png");
for(var pixel of image.values()){
    if(pixel.getX()<50 & pixel.getY()<50){
        pixel.setRed(0);
        pixel.setGreen(255);
        pixel.setBlue(0);
    }
}
print(image);

效果

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7. 制作一个渐变效果的红色块

function changeRed(width, height) {
    var picture = new SimpleImage(width, height);
    for(var pixel of picture.values()){
        pixel.setRed(pixel.getX());
        pixel.setGreen(0);
        pixel.setBlue(0);
    }
    return picture;
}

var result = changeRed(256,200);
print(result);

效果

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8. 在7的基础上更好看一些

function changeRed(width, height) {
    var picture = new SimpleImage(width, height);
    for(var pixel of picture.values()){
        pixel.setRed(pixel.getX());
        pixel.setGreen(200);
        pixel.setBlue(100);
    }
    return picture;
}

var result = changeRed(256,200);
print(result);

效果

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