java - 处理绘图问题

Question

我对处理有点陌生，所以请耐心等待。我正在创建一个基本的绘图程序，您可以在其中单击一个彩色框来获取该颜色，然后您就可以进行绘图和其他操作。好吧，我已经创建了一个红色框颜色和一个橡皮擦，所以我决定创建一个蓝色框，但是当我单击它时，它不会将颜色更改为蓝色。我尝试过对此问题进行故障排除，但没有成功。

这是代码(请注意，这最适合 Eclipse 并导入处理核心 https://processing.org/tutorials/eclipse/ ):

// note: many imports aren't used yet
import java.util.ArrayList;
import java.util.Scanner;
import processing.core.PApplet;
import processing.core.PShape;

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class Main extends PApplet{

PShape rectangle;

int color;
int color2;
int color3;
boolean red = false;
boolean blue = false;
boolean green = false;
boolean eraser = false;

// needed to create this in order for Eclipse to work
public static void main(String[] args) {
    PApplet.main("Main");
}

public void settings(){
    size(1280, 720);
}

public void setup() {
    size(1280, 720);
    smooth();
    background(255, 255, 255);
    noStroke();

}

public void draw() {
    // nothing here yet
    if (keyPressed) {

    }
    else {
        color = 0;
    }
    fill(0);

    fill(255, 0, 0);
    // red square
    rect(0, 50, 50, 50);
    fill(0, 10, 255);
    // blue square
    rect(0, 100, 50, 50);
    fill(0);


}

public void mousePressed() {
    if(red) {
        color = 255;
        color2 = 0;
        color3 = 0;
    }
    if(eraser) {
        color = 255;
        color2 = 255;
        color3 = 255;
    }
    if(blue) {
        color = 0;
        color = 10;
        color = 255;
    }
    else{
        fill(0);
    }
    // check if mouse is in drawing area
    if (mouseX >= 50 && mouseX <= 1280 && mouseY >= 0 && mouseY <= 720) {
        // change the drawing color 
        fill(color, color2, color3);
        rect(mouseX, mouseY, 50, 50);
    }
    // if red
    if (mouseX >= 0 && mouseX <= 50 && mouseY >= 50 && mouseY <= 100) {
        eraser = false;
        blue = false;
        red = true;
    }
    // if eraser (note: in top left corner)
    if (mouseX >= 0 && mouseX <= 50 && mouseY >= 0 && mouseY <= 50) {
        red = false;
        blue = false;
        eraser = true;
    }
    // if blue
    if (mouseX >= 0 && mouseX <=50 && mouseY >= 100 && mouseY <= 150) {
        eraser = false;
        red = false;
        blue = true;
    }
}

// basically the same code for mousePressed
public void mouseDragged() {
    if(red) {
        color = 255;
        color2 = 0;
        color3 = 0;
    }
    if(eraser) {
        color = 255;
        color2 = 255;
        color3 = 255;
    }
    if(blue) {
        color = 0;
        color = 10;
        color = 255;
    }
    if (mouseX >= 50 && mouseX <= 1280 && mouseY >= 0 && mouseY <= 720) {
        fill(color, color2, color3);
        rect(mouseX, mouseY, 50, 50);
    }
    if (mouseX >= 0 && mouseX <= 50 && mouseY >= 50 && mouseY <= 100) {
        eraser = false;
        blue = false;
        red = true;
    }
    if (mouseX >= 0 && mouseX <= 50 && mouseY >= 0 && mouseY <= 50) {
        red = false;
        blue = false;
        eraser = true;
    }
    if (mouseX >= 0 && mouseX <=50 && mouseY >= 100 && mouseY <= 150) {
        eraser = false;
        red = false;
        blue = true;
    }
}

}

Answer 1

首先，您不应该使用名为 color 的变量。如果您使用的是 eclipse，这可能不会导致错误，但它会令人困惑，因为它与处理的特殊 color 数据类型冲突。

其次，看看这个 if 语句:

if(blue) {
    color = 0;
    color = 10;
    color = 255;
}

您只是一遍又一遍地设置颜色。也许您打算使用 color2 和 color3？

该 if 语句位于两个不同的位置。如果我将其更改为 color1、color2 和 color3，您的代码就可以正常工作。