在这里实现了上一个小节中没有实现的p_rgbt函数
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118
fb3/README.md
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118
fb3/README.md
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**（一）：写在前面**
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在这个小节中，主要介绍了frame buffer中的R,G,B以及透明度的位域属性．由于在上一个小节当中，我自私的以为这几个位域能够获得相应的R,G,B以及透明度的数值，然后再将其转化为图像，但是，经过我后来的学习，发现我错了．正确的将frame buffer读取并转换为图像的方法是首先读取(read)frame buffer，然后，再将读取的char数组转换为相应的图片．所以，后面，着重学习如何读取frame buffer，以及如何将其转化为图片．
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**（二）：R,G,B以及透明度位域**
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在fb.h头文件中的结构 fb_var_screeninfo中定义了R,G,B以及透明度的位域，他们都是一个结构体fb_bitfield的一个实例．下面我们来看一下bitfield的定义：
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```
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struct fb_bitfield {
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__u32 offset; /* 位域的开始 */
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__u32 length; /* length of bitfield 位域的长度 */
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__u32 msb_right; /* != 0 : Most significant bit is right 不等于０，大多数重要的位是右边的 */
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};
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```
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那么如果要打印该值的话，我们就需要使用该结构体．
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**（三）：完善上一节中的p_rgbt(PFBDEV pFbdev)函数**
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在我们的上一节中，我们留下了这个函数而没有去实现，这个来源于我的无知．所以，现在我们来完善一下这个函数．在上面我们知道这个关系之后，这个函数的实现就显得相对简单了．
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```
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//打印R,G,B和透明度
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void p_rgbt(PFBDEV pFbdev)
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{
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//R位域
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printf("R位域:\n");
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struct fb_bitfield bf = pFbdev->fb_var.red;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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//G位域
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printf("G位域:\n");
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bf = pFbdev->fb_var.green;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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// B位域
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printf("B位域:\n");
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bf = pFbdev->fb_var.blue;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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// 透明度位域
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printf("透明度位域:\n");
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bf = pFbdev->fb_var.transp;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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}
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```
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**（四）：编译运行方法**
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编译和运行方法和上一节的编译运行方法是一样的．
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**（五）：运行结果展示**
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下面我们来看一下我们的运行结果：
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```
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frame buffer所占内存的开始地址为:-1341710336
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frame buffer 的类型为:0
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frame buffer的可见清晰度为：
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x = 1366
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y = 768
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frame buffer的虚拟清晰度为：
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x = 1366
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y = 768
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frame buffer的虚拟分辨率到可见分辨率的偏移量为:
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x = 0
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y = 0
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frame buffer的BPP为：32
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R位域:
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开始:16
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长度:8
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MSB:0
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G位域:
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开始:8
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长度:8
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MSB:0
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B位域:
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开始:0
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长度:8
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MSB:0
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透明度位域:
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开始:0
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长度:0
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MSB:0
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frame buffer在内存中所占的高度和宽度分别是:
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宽度 = -1
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高度 = -1
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R位域:
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开始:16
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长度:8
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MSB:0
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G位域:
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开始:8
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长度:8
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MSB:0
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B位域:
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开始:0
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长度:8
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MSB:0
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透明度位域:
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开始:0
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长度:0
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MSB:0
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```
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**（六）：写在后面**
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今天很残酷，明天很残酷，后天很没有，但是绝大多数人死在了明天晚上．－－－－马云
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133
fb3/fbtool.c
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133
fb3/fbtool.c
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#include "fbtool.h"
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//打开并且初始化该frame buffer
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int fb_open(PFBDEV pFbdev)
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{
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//打开frame buffer
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pFbdev->fb = open(pFbdev->dev,O_RDWR);
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if(pFbdev->fb < 0)
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{
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printf("打开错误 %s : %n.请检查内核配置\n",pFbdev->dev);
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return 0;
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}
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// 初始化fb_var
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if(-1 == ioctl(pFbdev->fb,FBIOGET_VSCREENINFO,&(pFbdev->fb_var)))
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{
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printf("ioctl FBIOGET_VSCREENINFO\n");
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return 0;
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}
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// 初始化fb_fix
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if(-1 == ioctl(pFbdev->fb,FBIOGET_FSCREENINFO,&(pFbdev->fb_fix)))
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{
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printf("ioctl FBIOGET_FSCREENINFO\n");
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return 0;
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}
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return 1;
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}
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//关闭frame buffer
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int fb_close(PFBDEV pFbdev)
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{
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close(pFbdev->fb);
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pFbdev->fb = -1;
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}
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//打印frame buffer 所占内存的开始地址
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void pmem_start(PFBDEV pFbdev)
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{
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printf("frame buffer所占内存的开始地址为:%d\n",pFbdev->fb_fix.smem_start);
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}
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//打印FB_TYPE
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void p_type(PFBDEV pFbdev)
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{
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printf("frame buffer 的类型为:%d\n",pFbdev->fb_fix.type);
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}
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//打印可见清晰度
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void p_visible_res(PFBDEV pFbdev)
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{
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printf("frame buffer的可见清晰度为：\n\tx = %d\n\ty = %d\n",pFbdev->fb_var.xres,pFbdev->fb_var.yres);
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}
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//打印虚拟分辨率
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void p_virt_res(PFBDEV pFbdev)
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{
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printf("frame buffer的虚拟清晰度为：\n\tx = %d\n\ty = %d\n",pFbdev->fb_var.xres_virtual,pFbdev->fb_var.yres_virtual);
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}
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//打印虚拟到可见的偏移量
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void p_offset(PFBDEV pFbdev)
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{
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printf("frame buffer的虚拟分辨率到可见分辨率的偏移量为:\n\tx = %d\n\ty = %d\n",pFbdev->fb_var.xoffset,pFbdev->fb_var.yoffset);
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}
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//打印每个像素的位数
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void p_bpp(PFBDEV pFbdev)
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{
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printf("frame buffer的BPP为：%d\n",pFbdev->fb_var.bits_per_pixel);
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}
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//打印R,G,B和透明度
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void p_rgbt(PFBDEV pFbdev)
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{
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//R位域
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printf("R位域:\n");
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struct fb_bitfield bf = pFbdev->fb_var.red;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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//G位域
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printf("G位域:\n");
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bf = pFbdev->fb_var.green;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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// B位域
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printf("B位域:\n");
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bf = pFbdev->fb_var.blue;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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// 透明度位域
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printf("透明度位域:\n");
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bf = pFbdev->fb_var.transp;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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}
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//打印在内存中的高度和宽度
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void p_hw(PFBDEV pFbdev)
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{
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printf("frame buffer在内存中所占的高度和宽度分别是:\n\t宽度 = %d\n\t高度 = %d\n",pFbdev->fb_var.height,pFbdev->fb_var.width);
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}
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133
fb3/fbtool.c~
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133
fb3/fbtool.c~
Normal file
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#include "fbtool.h"
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//打开并且初始化该frame buffer
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int fb_open(PFBDEV pFbdev)
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{
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//打开frame buffer
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pFbdev->fb = open(pFbdev->dev,O_RDWR);
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if(pFbdev->fb < 0)
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{
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printf("打开错误 %s : %n.请检查内核配置\n",pFbdev->dev);
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return 0;
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}
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// 初始化fb_var
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if(-1 == ioctl(pFbdev->fb,FBIOGET_VSCREENINFO,&(pFbdev->fb_var)))
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{
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printf("ioctl FBIOGET_VSCREENINFO\n");
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return 0;
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}
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// 初始化fb_fix
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if(-1 == ioctl(pFbdev->fb,FBIOGET_FSCREENINFO,&(pFbdev->fb_fix)))
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{
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printf("ioctl FBIOGET_FSCREENINFO\n");
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return 0;
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}
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return 1;
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}
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//关闭frame buffer
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int fb_close(PFBDEV pFbdev)
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{
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close(pFbdev->fb);
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pFbdev->fb = -1;
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}
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//打印frame buffer 所占内存的开始地址
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void pmem_start(PFBDEV pFbdev)
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{
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printf("frame buffer所占内存的开始地址为:%d\n",pFbdev->fb_fix.smem_start);
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}
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//打印FB_TYPE
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void p_type(PFBDEV pFbdev)
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{
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printf("frame buffer 的类型为:%d\n",pFbdev->fb_fix.type);
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}
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//打印可见清晰度
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void p_visible_res(PFBDEV pFbdev)
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{
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printf("frame buffer的可见清晰度为：\n\tx = %d\n\ty = %d\n",pFbdev->fb_var.xres,pFbdev->fb_var.yres);
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}
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//打印虚拟分辨率
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void p_virt_res(PFBDEV pFbdev)
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{
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printf("frame buffer的虚拟清晰度为：\n\tx = %d\n\ty = %d\n",pFbdev->fb_var.xres_virtual,pFbdev->fb_var.yres_virtual);
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}
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//打印虚拟到可见的偏移量
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void p_offset(PFBDEV pFbdev)
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{
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printf("frame buffer的虚拟分辨率到可见分辨率的偏移量为:\n\tx = %d\n\ty = %d\n",pFbdev->fb_var.xoffset,pFbdev->fb_var.yoffset);
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}
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//打印每个像素的位数
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void p_bpp(PFBDEV pFbdev)
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{
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printf("frame buffer的BPP为：%d\n",pFbdev->fb_var.bits_per_pixel);
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}
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//打印R,G,B和透明度
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void p_rgbt(PFBDEV pFbdev)
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{
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//R位域
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printf("R位域:\n");
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struct fb_bitfield bf = pFbdev->fb_var.red;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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//G位域
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printf("G位域:\n");
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bf = pFbdev->fb_var.green;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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// B位域
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printf("B位域:\n");
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bf = pFbdev->fb_var.blue;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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// 透明度位域
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printf("透明度位域:\n");
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bf = pFbdev->fb_var.transp;
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printf("\t开始:%d\n",bf.offset);
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printf("\t长度:%d\n",bf.length);
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printf("\tMSB:%d\n",bf.msb_right);
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}
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//打印在内存中的高度和宽度
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void p_hw(PFBDEV pFbdev)
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{
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printf("frame buffer在内存中所占的高度和宽度分别是:\n\t宽度 = %d\n\t高度 = %d\n",pFbdev->fb_var.height,pFbdev->fb_var.width);
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}
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41
fb3/fbtool.h
Normal file
41
fb3/fbtool.h
Normal file
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#ifndef __FBTOOL_H_
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#define __FBTOOL_H_
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#include <sys/ioctl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <linux/fb.h>
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#include <stddef.h>
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#include <string.h>
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typedef struct fbdev{
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int fb; //framebuffer打开后的唯一标识符
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struct fb_fix_screeninfo fb_fix;
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struct fb_var_screeninfo fb_var;
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char dev[20];
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}FBDEV,*PFBDEV;
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//打开framebuffer
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int fb_open(PFBDEV pFbdev);
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//关闭framebuffer
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int fb_close(PFBDEV pFbdev);
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//打印frame buffer 所占内存的开始地址
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void pmem_start(PFBDEV pFbdev);
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//打印FB_TYPE
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void p_type(PFBDEV pFbdev);
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//打印可见清晰度
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void p_visible_res(PFBDEV pFbdev);
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//打印虚拟分辨率
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void p_virt_res(PFBDEV pFbdev);
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//打印虚拟到可见的偏移量
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void p_offset(PFBDEV pFbdev);
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//打印每个像素的位数
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void p_bpp(PFBDEV pFbdev);
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//打印R,G,B和透明度
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void p_rgbt(PFBDEV pFbdev);
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//打印在内存中的高度和宽度
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void p_hw(PFBDEV pFbdev);
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#endif
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41
fb3/fbtool.h~
Normal file
41
fb3/fbtool.h~
Normal file
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#ifndef __FBTOOL_H_
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#define __FBTOOL_H_
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#include <sys/ioctl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <linux/fb.h>
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#include <stddef.h>
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#include <string.h>
|
||||
|
||||
typedef struct fbdev{
|
||||
int fb; //framebuffer打开后的唯一标识符
|
||||
struct fb_fix_screeninfo fb_fix;
|
||||
struct fb_var_screeninfo fb_var;
|
||||
char dev[20];
|
||||
}FBDEV,*PFBDEV;
|
||||
|
||||
//打开framebuffer
|
||||
int fb_open(PFBDEV pFbdev);
|
||||
//关闭framebuffer
|
||||
int fb_close(PFBDEV pFbdev);
|
||||
//打印frame buffer 所占内存的开始地址
|
||||
void pmem_start(PFBDEV pFbdev);
|
||||
//打印FB_TYPE
|
||||
void p_type(PFBDEV pFbdev);
|
||||
//打印可见清晰度
|
||||
void p_visible_res(PFBDEV pFbdev);
|
||||
//打印虚拟分辨率
|
||||
void p_virt_res(PFBDEV pFbdev);
|
||||
//打印虚拟到可见的偏移量
|
||||
void p_offset(PFBDEV pFbdev);
|
||||
//打印每个像素的位数
|
||||
void p_bpp(PFBDEV pFbdev);
|
||||
//打印R,G,B和透明度
|
||||
void p_rgbt(PFBDEV pFbdev);
|
||||
//打印在内存中的高度和宽度
|
||||
void p_hw(PFBDEV pFbdev);
|
||||
|
||||
#endif
|
||||
37
fb3/test.c
Normal file
37
fb3/test.c
Normal file
@ -0,0 +1,37 @@
|
||||
#include "fbtool.h"
|
||||
|
||||
int main()
|
||||
{
|
||||
FBDEV fbdev;
|
||||
|
||||
memset(&fbdev,0,sizeof(FBDEV));
|
||||
strcpy(fbdev.dev,"/dev/fb0");
|
||||
|
||||
if(0 == fb_open(&fbdev)){
|
||||
printf("Open fail!!\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
//打印frame buffer 所占内存的开始地址
|
||||
pmem_start(&fbdev);
|
||||
//打印FB_TYPE
|
||||
p_type(&fbdev);
|
||||
//打印可见清晰度
|
||||
p_visible_res(&fbdev);
|
||||
//打印虚拟分辨率
|
||||
p_virt_res(&fbdev);
|
||||
//打印虚拟到可见的偏移量
|
||||
p_offset(&fbdev);
|
||||
//打印每个像素的位数
|
||||
p_bpp(&fbdev);
|
||||
//打印R,G,B和透明度
|
||||
p_rgbt(&fbdev);
|
||||
//打印在内存中的高度和宽度
|
||||
p_hw(&fbdev);
|
||||
//打印fb的RGB和透明度的位域
|
||||
p_rgbt(&fbdev);
|
||||
|
||||
fb_close(&fbdev);
|
||||
|
||||
return 0;
|
||||
}
|
||||
38
fb3/test.c~
Normal file
38
fb3/test.c~
Normal file
@ -0,0 +1,38 @@
|
||||
#include "fbtool.h"
|
||||
|
||||
int main()
|
||||
{
|
||||
FBDEV fbdev;
|
||||
|
||||
memset(&fbdev,0,sizeof(FBDEV));
|
||||
strcpy(fbdev.dev,"/dev/fb0");
|
||||
|
||||
if(0 == fb_open(&fbdev)){
|
||||
printf("Open fail!!\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
|
||||
//打印frame buffer 所占内存的开始地址
|
||||
pmem_start(&fbdev);
|
||||
//打印FB_TYPE
|
||||
p_type(&fbdev);
|
||||
//打印可见清晰度
|
||||
p_visible_res(&fbdev);
|
||||
//打印虚拟分辨率
|
||||
p_virt_res(&fbdev);
|
||||
//打印虚拟到可见的偏移量
|
||||
p_offset(&fbdev);
|
||||
//打印每个像素的位数
|
||||
p_bpp(&fbdev);
|
||||
//打印R,G,B和透明度
|
||||
p_rgbt(&fbdev);
|
||||
//打印在内存中的高度和宽度
|
||||
p_hw(&fbdev);
|
||||
//打印fb的RGB和透明度的位域
|
||||
p_rgbt(&fbdev);
|
||||
|
||||
fb_close(&fbdev);
|
||||
|
||||
return 0;
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user