雙緩沖技術(shù)的應(yīng)用很廣泛，設(shè)計(jì)游戲的時(shí)候更是需要它，
???? 在midp1.0中，api中并沒有g(shù)ame這個(gè)包，看到網(wǎng)上很多人在討論設(shè)計(jì)游戲的時(shí)候會(huì)出現(xiàn)圖片斷裂，屏幕閃爍等問題。
???? 我經(jīng)過這幾天的學(xué)習(xí)整理下自己的學(xué)習(xí)心得，用來拋磚，希望對(duì)此有研究高手們相互討論。讓我也學(xué)習(xí)學(xué)習(xí)。
????
???? 雙緩沖的原理可以這樣形象的理解：把電腦屏幕看作一塊黑板。首先我們?cè)趦?nèi)存環(huán)境中建立一個(gè)“虛擬“的黑板，然后在這塊黑板上繪制復(fù)雜的圖形，等圖形全部繪制完畢的時(shí)候，再一次性的把內(nèi)存中繪制好的圖形“拷貝”到另一塊黑板（屏幕）上。采取這種方法可以提高繪圖速度，極大的改善繪圖效果。
??? 對(duì)于手機(jī)來說。具體的過程就是通過extends Canvas。然后獲取bufferImage。再然后就getGraphics。最后就是在這個(gè)graphics中繪制圖片等，再最后就是把這個(gè)繪制好的bufferImage繪制的屏幕上。
???? 說歸說。具體還是要看代碼的。里面的代碼參照了一些開源的代碼。
java 代碼
- package?org.wuhua.game;??
- ??
- import?javax.microedition.lcdui.Canvas;??
- import?javax.microedition.lcdui.Graphics;??
- import?javax.microedition.lcdui.Image;??
- ??
?
- ??
- ?
- ?
- ?
- ?
- ?
- ?
- ?
- ?
- ??
- public?abstract?class?GameCanvas?extends?Canvas?{??
- ??
- ?????
- ?
- ??
- ????private?Image?bufferImage;??
- ??
- ????private?int?height;??
- ??
- ????private?int?width;??
- ??
- ????private?int?clipX,?clipY,?clipWidth,?clipHeight;??
- ??
- ????private?boolean?setClip;??
- ??
- ????protected?GameCanvas()?{??
- ??
- ????????super();??
- ??
- ????????width?=?getWidth();??
- ????????height?=?getHeight();??
- ??
- ????????this.bufferImage?=?Image.createImage(width,?height);??
- ??
- ????}??
- ??
- ????protected?void?paint(Graphics?g)?{??
- ??????????
- ????????if?(this.setClip)?{??
- ????????????g.clipRect(this.clipX,?this.clipY,?this.clipWidth,?this.clipHeight);??
- ????????????this.setClip?=?false;??
- ????????}??
- ????????g.drawImage(this.bufferImage,?0,?0,?Graphics.TOP?|?Graphics.LEFT);??
- ??
- ????}??
- ??
- ????public?void?flushGraphics(int?x,?int?y,?int?width,?int?height)?{??
- ????????this.setClip?=?true;??
- ????????this.clipX?=?x;??
- ????????this.clipY?=?y;??
- ????????this.clipWidth?=?width;??
- ????????this.clipHeight?=?height;??
- ??
- ????????repaint();??
- ????????serviceRepaints();??
- ????}??
- ??
- ????public?void?flushGraphics()?{??
- ????????repaint();??
- ????????serviceRepaints();??
- ????}??
- ??
- ?????
- ?
- ?
- ??
- ????protected?Graphics?getGraphics()?{??
- ????????return?this.bufferImage.getGraphics();??
- ????}??
- ??
- ?????
- ?
- ??
- ????protected?final?void?sizeChanged(int?w,?int?h)?{??
- ????????if?(h?>?height)?{??
- ????????????this.bufferImage?=?Image.createImage(w,?h);??
- ????????}??
- ????}??
- }?