Cocos2dx进阶学习之屏幕适配

背景

在学习cocos2dx时，咱们在main函数中发现一句代码，

 1 #include "main.h"   2    3 #include "AppDelegate.h"   4    5 #include "CCEGLView.h"   6    7      8    9 USING_NS_CC;  10   11     12   13 int APIENTRY _tWinMain(HINSTANCE hInstance,  14   15                        HINSTANCE hPrevInstance,  16   17                        LPTSTR    lpCmdLine,  18   19                        int       nCmdShow)  20   21 {  22   23     UNREFERENCED_PARAMETER(hPrevInstance);  24   25     UNREFERENCED_PARAMETER(lpCmdLine);  26   27     28   29     // create the application instance  
30   31     AppDelegate app;  32   33     CCEGLView* eglView = CCEGLView::sharedOpenGLView();  34   35     eglView->setViewName("CrazyMario");  36   37     eglView->setFrameSize(480, 320);  38   39     return CCApplication::sharedApplication()->run();  40   41 }

那就是eglView->setFrameSize(480,320)，这句代码设置了窗口的大小，通常说来手机游戏须要全屏显示，因此对于不一样分辨率的手机，setFrameSize要求不同的。这样是否是很崩溃？由于咱们代码里不少地方可能也要改，图片大小可能也要改，那怎么办呢？

其实cocos2dx已经为咱们作好了这一切

结局方案

这个方案就是调用eglView->setDesignResolutionSize(480, 320, kResolutionShowAll);来告诉cocos2dx，个人程序是按照480，320来设计的，那么setFrameSize若是不是480，320那么cocos2dx会按照比例给咱们作适配，不用咱们作别的事情。

在超级马里奥这个游戏里，在AppDelegate中已经调用了setDesignResolutionSize函数设置设计大小为480，320。

那么在setFrameSize不一样的状况下，也不会引发图片比例不合适的状况，只是窗口大小会发生变化而已

在480*320的状况下

在960*640的状况下，只是界面变大了，图片没有任何的不适合

 

setDesignResolutionSize的参数

第三个参数的取值范围以下： 

 1 enum ResolutionPolicy  2 {  3     // The entire application is visible in the specified area without trying to preserve the original aspect ratio.  4     // Distortion can occur, and the application may appear stretched or compressed.
 5     kResolutionExactFit,  6     // The entire application fills the specified area, without distortion but possibly with some cropping,  7     // while maintaining the original aspect ratio of the application.
 8     kResolutionNoBorder,  9     // The entire application is visible in the specified area without distortion while maintaining the original 10     // aspect ratio of the application. Borders can appear on two sides of the application.
11     kResolutionShowAll, 12     // The application takes the height of the design resolution size and modifies the width of the internal 13     // canvas so that it fits the aspect ratio of the device 14     // no distortion will occur however you must make sure your application works on different 15     // aspect ratios
16     kResolutionFixedHeight, 17     // The application takes the width of the design resolution size and modifies the height of the internal 18     // canvas so that it fits the aspect ratio of the device 19     // no distortion will occur however you must make sure your application works on different 20     // aspect ratios
21     kResolutionFixedWidth, 22   23     kResolutionUnKnown, 24 };

kResolutionExactFit：会靠拉伸来填满屏幕，本例来讲背景图会变形来填充屏幕，由于1024:768=1.3， 480:320=1.5，宽高比不一样，图片也就没法等比缩放来填满屏幕，只能变形了。

kResolutionNoBorder： 看不到黑边，实际就是宽高等比缩放，但缩放比例取宽比和高比之中大的那一个。

kResolutionShowAll：所有显示，能够理解为保证内容都显示在屏幕以内，实际也是宽高等比缩放，但缩放比例取宽比和高比之中小的那一个。