canvas图像.docx

1、canvas图像/ 原点坐标转换应用/import javax.microedition.midlet.;import javax.microedition.lcdui.;public class canvasDemo5 extends MIDlet Display display; canvasTranslate canvastranslate; public canvasDemo5() canvastranslate=new canvasTranslate(); display=Display.getDisplay(this); public void startApp() display

2、.setCurrent(canvastranslate); public void pauseApp() public void destroyApp(boolean unconditional) class canvasTranslate extends Canvas int gameaction=0; int x; int y; boolean view; Image pictureImage; public canvasTranslate() try pictureImage=Image.createImage(/picture.png); catch(Exception ex) pub

3、lic void keyPressed(int keyCode) gameaction=getGameAction(keyCode); switch(gameaction) case UP: view=false; repaint(); break; case DOWN: view=true; /设置X, Y轴位移量 x=50; y=60; repaint(); break; public void paint(Graphics g) g.setColor(0xFFFFFF); g.fillRect(0,0,getWidth(),getHeight(); g.setColor(0); if(v

4、iew) /设置变换原点坐标，位移至(x,y) g.translate(x,y); /取得X轴位移量 g.drawString(X轴位移+String.valueOf(g.getTranslateX(), -10, -40, Graphics.LEFT | Graphics.TOP); /取得Y轴位移量 g.drawString(Y轴位移+String.valueOf(g.getTranslateY(), -10, -20, Graphics.LEFT | Graphics.TOP); /保持图片都在原始点(0,0) 显示 g.drawImage(pictureImage, 0, 0, Gra

5、phics.LEFT | Graphics.TOP); 运行结果如图6-18所示。 图6-186.5.2 图片切割法第二个应用是Graphics类对图片处理的另一种方法，就是指定图片显示区域的位置，就像是图片被切割一样。如示例6-9中根据设计者需求进行图片画面设置，可以调用方法：l public void setClip (int x, int y, int width, int height)设置图片的切割范围，范围定义坐标为(x, y)、宽度width、高度height。l public int getClipX ()取得切割图片的X坐标值。l public int getClipY ()

6、取得切割图片的Y坐标值。l public int getClipWidth ()取得切割图片的宽度值。l ublic int getClipHeight ()取得切割图片的高度值。l public void clipRect (int x, int y, int width, int height)指定矩形区域与图片重叠处才显示，定义坐标为(x, y)，指定矩形的宽度width、高度height。示例6-9/ 图片切割状态显示/import javax.microedition.midlet.;import javax.microedition.lcdui.;import java.util.

7、Random;public class canvasDemo6 extends MIDlet Display display; canvasClip canvasclip; public canvasDemo6() canvasclip=new canvasClip(); display=Display.getDisplay(this); public void startApp() display.setCurrent(canvasclip); public void pauseApp() public void destroyApp(boolean unconditional) class

8、 canvasClip extends Canvas int gameaction=0; int x=0; int y=0; int width; int height; Image pictureImage; Random viewRand; public canvasClip() try pictureImage=Image.createImage(/picture.png); catch(Exception ex) public void keyPressed(int keyCode) gameaction=getGameAction(keyCode); viewRand=new Ran

9、dom(); x=(int)Math.abs(viewRand.nextInt()%60); y=(int)Math.abs(viewRand.nextInt()%60); switch(gameaction) case FIRE: repaint(); break; public void paint(Graphics g) g.setColor(0xFFFFFF); g.fillRect(0,0,getWidth(),getHeight(); g.setColor(0); /设置切割区域 g.setClip(30, 60, x, y); /取得切割画面的宽度 width=g.getClip

10、Width(); /取得切割画面的高度 height=g.getClipHeight(); g.drawImage(pictureImage, 30, 60, Graphics.LEFT | Graphics.TOP); /将切割后的动作应用到全屏幕画面 g.setClip(0, 0, getWidth(), getHeight(); g.drawString(宽度:+width, 50, 10, Graphics.HCENTER | Graphics. TOP); g.drawString(高度:+height, 50, 30, Graphics.HCENTER | Graphics. TO

11、P); /进行矩形切割 g.clipRect(100, 60, x, y); /取得切割画面的矩形宽度 width=g.getClipWidth(); /取得切割画面的矩形宽度 height=g.getClipHeight(); g.drawImage(pictureImage, 100, 60, Graphics.LEFT | Graphics.TOP); /将切割后的动作应用到全屏幕画面 g.setClip(0, 0, getWidth(), getHeight(); g.drawString(矩形宽度:+width, 120, 10, Graphics.HCENTER | Graphic

12、s.TOP); g.drawString(矩形高度:+height, 120, 30, Graphics.HCENTER | Graphics.TOP); g.drawRect(100, 60, x, y); 运行结果如图6-19所示。 图6-19【说明】运行切割画面后，请注意一定要将画面恢复原状。也就是不管切割画面大小如何，最后一定要设g.setClip（0,0,getWidth(),getHeight()），除非设计游戏时有其他显示考虑。 6.5.3 合成图片动画制作第5章介绍过如何制作动画效果，当图片是为了缩小文件大小而合成整张时，程序编写也就会有所不同。主要是将转换坐标方法与切割图片方

13、法混合使用，达到显示动态图片的目的。将第5章合成一整张图片的方法进行修改，如图6-20所示。具体程序见示例6-10。图6-20 将图片组合成一张示意图示例6-10/ 整张图片制作成动画的应用/import javax.microedition.midlet.;import javax.microedition.lcdui.;import javax.microedition.io.;public class canvasDemo7 extends MIDlet Display display; canvasCAR canvascar; public canvasDemo7() canvasca

14、r=new canvasCAR(); display=Display.getDisplay(this); public void startApp() display.setCurrent(canvascar); public void pauseApp() public void destroyApp(boolean unconditional) class canvasCAR extends Canvas int gameaction, running; Image carImage; goCar gocar; int gorun= 14,123,14,113,14,103,14,93,1

15、4,83,14,73, 14,63,14,53,14,43,14,33,14,23,14,13, 24,13,34,13,44,13,54,13,64,13,74,13, 84,13,94,13,104,13,114,13,124,13,134,13, 134,23,134,33,134,43,134,53,134,63,134,73, 134,83,134,93,134,103,134,113,134,123,134,133, 124,133,114,133,104,133,94,133,84,133,74,133,64,133,54,133,44,133,34,133,24,133,14,

16、133 ; int imagetype= 0,0,0,0,0,0, 0,0,0,0,0,1, 2,2,2,2,2,2, 2,2,2,2,2,3, 4,4,4,4,4,4, 4,4,4,4,4,5, 6,6,6,6,6,6, 6,6,6,6,6,7, ; public canvasCAR() running=0; try carImage=Image.createImage(/car.png); catch(Exception ex) public void keyPressed(int keyCode) gameaction=getGameAction(keyCode); switch(gam

17、eaction) case UP: break; case DOWN: break; case LEFT: break; case RIGHT: break; case FIRE: gocar=new goCar(); gocar.start(); gocar=null; break; public void paint(Graphics g) g.setColor(0x90EE90); g.fillRect(0, 0, getWidth(), getHeight();/转换坐标系 g.translate(gorunrunning0-imagetyperunning32, gorunrunni

18、ng1);/切割显示图片 g.setClip(imagetyperunning32,0,32,32); /图片显示在屏幕上 g.drawImage(carImage, 0, 0, Graphics.LEFT | Graphics.TOP); /恢复图片的原点坐标系 g.translate(-gorunrunning0+imagetyperunning32, gorunrunning1); /线程运行图片显示 class goCar extends Thread public void run() while(true) try running+; if(running47) running=0; repaint(); Thread.sleep(200); catch(Exception ex)