嵌入式Linux下真彩Logo的实现

最新推荐文章于 2022-05-25 22:40:18 发布

Behard

最新推荐文章于 2022-05-25 22:40:18 发布

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分类专栏：嵌入式Linux 文章标签： linux 嵌入式 struct system file null

本文链接：https://blog.youkuaiyun.com/Behard/article/details/4512716

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1 篇文章

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目前嵌入式产品越来越多了，一般都能带Logo显示启动的。让我们来看看Logo显示是怎么做的(我仅仅做Linux方面的，没有做过WinCE的)。

参考一些嵌入式平台的做法，基本是fb_prepare_logo(struct fb_info *info, int rotate)、fb_show_logo(struct fb_info *info, int rotate)两个函数实现的。但是该两个函数其实没有参考的价值。最简单的做法就是调用该两个函数。
1. 在 xxx__probe(struct platform_device *dev) 函数 return 0 之前调用
#if defined(CONFIG_LOGO)
// 原来代码先检查info->fbcon_par->rotate是否为FB_ROTATE_UR，这里直接设置FB_ROTATE_UR
if (fb_prepare_logo(info, FB_ROTATE_UR))
{
  /* Start display and show logo on boot */
  /* fb_set_cmap(info->cmap, info); */
  /* Show the logo */
  fb_show_logo(info, FB_ROTATE_UR);
}
#endif
注意：struct fb_info *info = framebuffer_alloc(...);

2. 在编译内核时选择 Boot logo, Logo_clut224
3. 制作ppm格式logo文件
首先使用 Photoshop 制作 png 文件(Windows下)
再将png图片转成pnm(下面步骤为linux下，我使用CentOS 4.7，使用root权限用户)
# pngtopnm uclinux_logo.png > uclinux_logo.pnm
然后将pnm图片的颜色数限制在224
# pnmquant 224 uclinux_logo.pnm > logo_linux_clut224.pnm
最后将pnm图片转换成我们需要的ppm
# pnmtoplainpnm logo_linux_clut224.pnm > logo_linux_clut224.ppm
将 logo_linux_clut224.ppm 替换 linux-2.6/drivers/video/logo 中对应的图像
我在这里制作的文件是与分辨率同样大小的文件，如果小于分辨率的话，应该显示在左上角。

说实话，上面步骤制作的Logo最多为224色图片效果。能不能显示真彩的Logo呢？实际上肯定是可以的。
我的实现方法：制作自己的fb_prepare_logo、fb_show_logo函数，将真彩的颜色值直接写到Frame Buffer的内存中。

1. 将分辨率和颜色位数定义放到头文件中 truecolor_logo.h
我的定义为
#define XRES 800 /* The pixel width of the LCD */
#define YRES 480 /* The pixel height of the LCD */
#define BPX 32 /* The bits depth of the LCD */

2. 增加一个 truecolor_logo.c 文件，将该文件加入到内核中，该文件实现
int fb_prepare_truecolor_logo(void)、void fb_show_truecolor_logo(struct fb_info *info) 两个函数
static struct TrueColor
{
    int Width, Height;
    int ColorBytes;
    const char *BitData;
} _true_color_logo;
static unsigned char truecolor_logo_data[] = { ... }; 读取图片的颜色值赋值到这里
int fb_prepare_truecolor_logo(void)
{
_true_color_logo.ColorBytes = BPX/8;
_true_color_logo.Width = 351; /* 这里要与truecolor_logo_data的长度相对应 */
_true_color_logo.Height = 137;
_true_color_logo.BitData = truecolor_logo_data;
printk("fb_prepare_truecolor_logo ok /n");
return (_true_color_logo.ColorBytes > 1); /* 仅仅支持 16 位色或者更高位色 */
}

void fb_show_truecolor_logo(struct fb_info *info)
{
char *framebase = info->screen_base;
int m, n;
int startx, starty;

startx = (XRES- _true_color_logo.Width)/ 2;
if(startx < 0) startx = 0;
starty = (YRES- _true_color_logo.Height)/ 2;
if(starty < 0) starty = 0;

for(m=0; m<YRES; m++)
{
  /* 设置图片之外(上、下部)是背景色为黑色 */
  if((m < starty) || (m >= _true_color_logo.Height+starty))
  {
   memset(framebase+ (m* XRES* _true_color_logo.ColorBytes), 0, XRES* _true_color_logo.ColorBytes);
  }
  else
  {
   /* 设置图片之外(左边)是背景色为黑色 */
   memset(framebase+ ((m* XRES)* _true_color_logo.ColorBytes), 0, _true_color_logo.ColorBytes* startx);

   /* 将 Logo 显示在中间, 图片上下需要翻转 */
   memcpy(framebase+ ((m* XRES+ startx)* _true_color_logo.ColorBytes),
    // (_true_color_logo.BitData+ ((m-starty)* _true_color_logo.Width)* _true_color_logo.ColorBytes),
    (_true_color_logo.BitData+ ((_true_color_logo.Height-(m-starty)-1)* _true_color_logo.Width)* _true_color_logo.ColorBytes),
    _true_color_logo.ColorBytes* _true_color_logo.Width);

   /* 设置图片之外(右边)是背景色为黑色 */
   memset(framebase+ ((m* XRES+ startx+ _true_color_logo.Width)* _true_color_logo.ColorBytes), 0,
    _true_color_logo.ColorBytes*(XRES- startx- _true_color_logo.Width));
  }
}
}

3. 修改 xxx__probe(struct platform_device *dev) 函数
#if defined(SHOW_TRUECOLOR_LOGO)

if(fb_prepare_truecolor_logo())

fb_show_truecolor_logo(info);

#elif defined(CONFIG_LOGO)
if (fb_prepare_logo(info, FB_ROTATE_UR))
{
  /* Start display and show logo on boot */
  /* fb_set_cmap(info->cmap, info); */ /* Cancel the code */
  /* Show the logo */
  fb_show_logo(info, FB_ROTATE_UR);
}
#endif

4. 为了方便，最好是设计一个自动生成 truecolor_logo.c 文件的程序
源代码如下：
/*
* Filename : bmp2logo.c

* Program : Transform the 24 bits's BMP to 16, 24, 32 bits logo tools

* Copyright : Copyright (C) 2009~2020 XXX Co., LTD.

* Author : behard
* Created at : 2009.01.09

*/
#include <stdio.h>
#include <stdlib.h>

typedef struct /* 24 bit BMP color */
{
unsigned char r;
unsigned char g;
unsigned char b;
} ColorBGR24BIT;

#define MAXROWTEXT 200

char strHead[][MAXROWTEXT] = {
"/*/r/n",
" * Filename : linux/drivers/video/truecolor_logo.c/r/n",

" * Program : Show the logo with 16, 24, 32 bits color not 224 colors/r/n",

" * Copyright : Copyright (C) 2009~2020 XXX Co., LTD./r/n",

" * Author     : behard/r/n",

" * Created at : 2009.01.09/r/n",

" *//r/n",

"#include <linux/module.h>/r/n",

"#include <linux/kernel.h>/r/n",

"#include <linux/errno.h>/r/n",

"#include <linux/string.h>/r/n",

"#include <linux/mm.h>/r/n",

"#include <linux/tty.h>/r/n",

"#include <linux/slab.h>/r/n",

"#include <linux/vmalloc.h>/r/n",

"#include <linux/delay.h>/r/n",

"#include <linux/interrupt.h>/r/n",

"#include <linux/dma-mapping.h>/r/n",

"#include <linux/platform_device.h>/r/n",

"/r/n",

"#include <asm/uaccess.h>/r/n",

"#include <linux/fb.h>/r/n",

"#include <linux/init.h>/r/n",

"/r/n",

"#include /"truecolor_logo.h/"/r/n",

"/r/n",

"// #define    DEBUG_TRUECOLOR_LOGO    /* Debug Output Switch *//r/n",

"/r/n",

"#ifdef CONFIG_FB_TRUECOLOR_LOGO/r/n",

"static struct TrueColor/r/n",

"{/r/n",

"    int Width, Height;/r/n",

"    int ColorBytes;/r/n",

"    const char *BitData;/r/n",

"} _true_color_logo;/r/n",
"/r/n",
};

int Tran_24bit_BMP(const char *BMPFile, const char *CxxFile)
{

int width, height;

short int bitcount;

FILE *fpBMP, *fpCxx;

ColorBGR24BIT *colorRead24; // read the color data(24 bit)
int i, j;

int out_counter;

unsigned short int Value_16;

fpBMP = fopen(BMPFile, "rb");

fpCxx = fopen(CxxFile, "wb");

if((NULL==fpBMP) || (NULL==fpCxx))
{
  if(NULL == fpBMP) printf("Read %s file failure. /n", BMPFile);
  else fclose(fpBMP);
  if(NULL == fpCxx) printf("Create %s file failure. /n", CxxFile);
  else fclose(fpCxx);
  return 0;
}

fseek(fpBMP, 18, SEEK_SET);
fread(&width, sizeof(width), 1, fpBMP);
fread(&height, sizeof(height), 1, fpBMP);
fseek(fpBMP, 28, SEEK_SET);
fread(&bitcount, sizeof(bitcount), 1, fpBMP);

printf("/n Width=%d, Height=%d Bits=%d./n", width, height, (int)bitcount);

if(24 != bitcount)

{

  fclose(fpBMP);

  fclose(fpCxx);

  printf("Only support 24 bitmap file. /n");
  return 0;

}

for(i=0; i<sizeof(strHead)/MAXROWTEXT; i++)

fprintf(fpCxx, strHead[i]);

// color * width memory
colorRead24 = (ColorBGR24BIT *)malloc(width* sizeof(ColorBGR24BIT));

// BPX==32
out_counter = 0;
fprintf(fpCxx, "#if (BPX==32)/r/n");
fprintf(fpCxx, "/r/n");
fprintf(fpCxx, "/* R(8)/G(8)/B(8)/0(8) code for little endian system *//r/n");
fprintf(fpCxx, "static unsigned char truecolor_logo_data[] =/r/n");
fprintf(fpCxx, "{/r/n");

fseek(fpBMP, 54, SEEK_SET);     // BMP file information head
for(j=height-1; j>=0; j--)
{
  fread(colorRead24, width*3, 1, fpBMP);
  if(width % 4) fseek(fpBMP, (width% 4), SEEK_CUR); // fix width and file pointer 24-bits

  for(i=0; i<width; i++)
  {
   if(0 == (out_counter % 6)) fprintf(fpCxx, "/r/n/t");
   out_counter++;
   // R/G/B/0 code for little endian system, the code for big endian system is not test
   fprintf(fpCxx, "0x%02x, 0x%02x, 0x%02x, 0x00, ", colorRead24[i].r, colorRead24[i].g, colorRead24[i].b);
  }
}
fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "};/r/n");

fprintf(fpCxx, "/r/n");

// BPX==24

out_counter = 0;

fprintf(fpCxx, "#elif (BPX==24)/r/n");
fprintf(fpCxx, "/r/n");
fprintf(fpCxx, "/* R(8)/G(8)/B(8) code for little endian system *//r/n");
fprintf(fpCxx, "static unsigned char truecolor_logo_data[] =/r/n");
fprintf(fpCxx, "{/r/n");

  for(i=0; i<width; i++)
  {
   if(0 == (out_counter % 8)) fprintf(fpCxx, "/r/n/t");
   out_counter++;
   // R/G/B: code for little endian system, the code for big endian system is not test
   fprintf(fpCxx, "0x%02x, 0x%02x, 0x%02x, ", colorRead24[i].r, colorRead24[i].g, colorRead24[i].b);
  }
}
fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "};/r/n");

fprintf(fpCxx, "/r/n");

// BPX==16

out_counter = 0;

fprintf(fpCxx, "#elif (BPX==16)/r/n");
fprintf(fpCxx, "/r/n");
fprintf(fpCxx, "/* R(5)/G(6)/B(5) code for little endian system *//r/n");
fprintf(fpCxx, "static unsigned char truecolor_logo_data[] =/r/n");
fprintf(fpCxx, "{/r/n");

  for(i=0; i<width; i++)
  {
   if(0 == (out_counter % 12)) fprintf(fpCxx, "/r/n/t");
   out_counter++;
   // R(5)/G(6)/B(5): code for little endian system
   Value_16 = ((colorRead24[i].r >> 3) << 11) | ((colorRead24[i].r >> 2) << 5) | (colorRead24[i].b >> 3);
   fprintf(fpCxx, "0x%02x, 0x%02x, ", (Value_16 >> 8), (Value_16 & 0xFF));
  }
}
fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "};/r/n");

fprintf(fpCxx, "/r/n");

// BPX < 16 (Don't support)

fprintf(fpCxx, "#else/r/n");

fprintf(fpCxx, "/r/n");
fprintf(fpCxx, "static unsigned char truecolor_logo_data[] =/r/n");
fprintf(fpCxx, "{ 0, }; /r/n");
fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "#endif // BPX /r/n");

fprintf(fpCxx, "/r/n");

// Set the logo data information and the fb_prepare_truecolor_logo function

fprintf(fpCxx, "int fb_prepare_truecolor_logo(void)/r/n");

fprintf(fpCxx, "{/r/n");
fprintf(fpCxx, "/t_true_color_logo.ColorBytes = BPX/8;/r/n");
fprintf(fpCxx, "/t_true_color_logo.Width = %d;/r/n", width);
fprintf(fpCxx, "/t_true_color_logo.Height = %d;/r/n", height);

fprintf(fpCxx, "/t_true_color_logo.BitData = truecolor_logo_data;/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "#ifdef DEBUG_TRUECOLOR_LOGO/r/n");

fprintf(fpCxx, "/tprintk(/"fb_prepare_truecolor_logo ok //n/");/r/n");

fprintf(fpCxx, "#endif/r/n");

fprintf(fpCxx, "/treturn (_true_color_logo.ColorBytes > 1); /* Only support 16 Bits or more color*//r/n");

fprintf(fpCxx, "}/r/n");

fprintf(fpCxx, "/r/n");

// Set the fb_show_truecolor_logo function

fprintf(fpCxx, "void fb_show_truecolor_logo(struct fb_info *info)/r/n");

fprintf(fpCxx, "{/r/n");

fprintf(fpCxx, "/tchar *framebase = info->screen_base;/r/n");

fprintf(fpCxx, "/tint m, n;/r/n");

fprintf(fpCxx, "/tint startx, starty;/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "/tstartx = (XRES- _true_color_logo.Width)/ 2;/r/n");

fprintf(fpCxx, "/tif(startx < 0) startx = 0;/r/n");

fprintf(fpCxx, "/tstarty = (YRES- _true_color_logo.Height)/ 2;/r/n");

fprintf(fpCxx, "/tif(starty < 0) starty = 0;/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "#ifdef DEBUG_TRUECOLOR_LOGO/r/n");

fprintf(fpCxx, "/tprintk(/"fb_show_truecolor_logo:: %%d %%d %%d %%d //n/", XRES, YRES, startx, starty);/r/n");

fprintf(fpCxx, "#endif/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "/tfor(m=0; m<YRES; m++)/r/n");

fprintf(fpCxx, "/t{/r/n");

fprintf(fpCxx, "/t/tif((m < starty) || (m >= _true_color_logo.Height+starty)) // Set the background color to black/r/n");

fprintf(fpCxx, "/t/t{/r/n");

fprintf(fpCxx, "/t/t/tmemset(framebase+ (m* XRES* _true_color_logo.ColorBytes), 0, XRES* _true_color_logo.ColorBytes);/r/n");

fprintf(fpCxx, "/t/t}/r/n");

fprintf(fpCxx, "/t/telse/r/n");

fprintf(fpCxx, "/t/t{/r/n");

fprintf(fpCxx, "/t/t/t// Set the left to black color/r/n");

fprintf(fpCxx, "/t/t/tmemset(framebase+ ((m* XRES)* _true_color_logo.ColorBytes), 0, _true_color_logo.ColorBytes* startx);/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "/t/t/t// Set logo data, the vertical must upend/r/n");

fprintf(fpCxx, "/t/t/tmemcpy(framebase+ ((m* XRES+ startx)* _true_color_logo.ColorBytes), /r/n");

fprintf(fpCxx, "/t/t/t/t// (_true_color_logo.BitData+ ((m-starty)* _true_color_logo.Width)* _true_color_logo.ColorBytes), /r/n");

fprintf(fpCxx, "/t/t/t/t(_true_color_logo.BitData+ ((_true_color_logo.Height-(m-starty)-1)* _true_color_logo.Width)* _true_color_logo.ColorBytes), /r/n");

fprintf(fpCxx, "/t/t/t/t_true_color_logo.ColorBytes* _true_color_logo.Width);/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "/t/t/t// Set the right to black color/r/n");

fprintf(fpCxx, "/t/t/tmemset(framebase+ ((m* XRES+ startx+ _true_color_logo.Width)* _true_color_logo.ColorBytes), 0, /r/n");

fprintf(fpCxx, "/t/t/t/t_true_color_logo.ColorBytes*(XRES- startx- _true_color_logo.Width));/r/n");

fprintf(fpCxx, "/t/t}/r/n");

fprintf(fpCxx, "/t}/r/n");

fprintf(fpCxx, "}/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "#else // CONFIG_FB_TRUECOLOR_LOGO/r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "int fb_prepare_truecolor_logo(void) { return 0; } /r/n");

fprintf(fpCxx, "void fb_show_truecolor_logo(struct fb_info *info) { return; } /r/n");

fprintf(fpCxx, "/r/n");

fprintf(fpCxx, "#endif // CONFIG_FB_TRUECOLOR_LOGO/r/n");

fprintf(fpCxx, "/r/n");

free(colorRead24);

fclose(fpBMP);

fclose(fpCxx);

return 1;

}

int main(int argc, char* argv[])
{
char CxxFileName[100];
if(argc < 2)
{
  printf("Use: bmp2logo xxx.bmp (truecolor_logo.c)/n");
#ifdef __WIN32__
  system("Pause");
#endif
  return;
}

if(argc > 2) strcpy(CxxFileName, argv[2]);
#ifdef __WIN32__
else strcpy(CxxFileName, ".//..//truecolor_logo.c");
#else
else strcpy(CxxFileName, "./../truecolor_logo.c");
#endif

if( ! (Tran_24bit_BMP(argv[1], CxxFileName)))
{
  printf("Transform %s to truecolor_logo.c failure /n", argv[1]);
#ifdef __WIN32__
  system("Pause");
#endif
  return -1;
}

printf("Transform %s to truecolor_logo.c success /n", argv[1]);
#ifdef __WIN32__
system("Pause");
#endif
return 0;
}