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https://github.com/Ascend/ascend_community_projects.git
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lqw
85 lines
2.4 KiB
C
85 lines
2.4 KiB
C
/**
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* Copyright(C) 2022. Huawei Technologies Co.,Ltd. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <sys/mman.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <linux/fb.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/ioctl.h>
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struct fb_var_screeninfo g_vinfo = {0}; // 定义结构体变量，读取屏幕信息时用来记录屏幕可变信息的
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unsigned char *g_fb_base; // 显存的基地址
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unsigned int g_line_length;
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unsigned int g_bytes_per_pixel; // 每像素占用字节数
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void set_pixel_color(int x, int y, unsigned int color) // 将坐标为(x,y)的像素设为指定颜色
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{
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int index = y * g_line_length + x * g_bytes_per_pixel;
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*(unsigned int *)(g_fb_base + index) = color;
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}
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int main(void)
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{
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int i, j;
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int bits_per_byte = 8;
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int pixels_per_color = 5;
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int width = 240;
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int height = 320;
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int color_num = 32;
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int fd_fb;
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int frame_buffer_size; // 显存大小
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fd_fb = open("/dev/fb0", O_RDWR); // 打开fb0
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if (fd_fb < 0)
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{
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perror("open");
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return -1;
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}
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if (ioctl(fd_fb, FBIOGET_VSCREENINFO, &g_vinfo)) // 获取可变的参数fb_var_screeninfo的值
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{
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perror("ioctl");
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return -1;
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}
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g_bytes_per_pixel = g_vinfo.bits_per_pixel / bits_per_byte;
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g_line_length = g_vinfo.xres_virtual * g_bytes_per_pixel;
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frame_buffer_size = g_vinfo.xres_virtual * g_vinfo.yres_virtual * g_bytes_per_pixel;
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g_fb_base = (unsigned char *)mmap(NULL, frame_buffer_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd_fb, 0); // 通过mmap获取显存地址
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if (g_fb_base == (unsigned char *)-1)
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{
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printf("can't mmap\n");
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return -1;
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}
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for (j = 0; j<height; j++)
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{
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for (i = 0; i<width; i++)
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{
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set_pixel_color(i, j, color_num * (j / pixels_per_color));
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}
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}
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munmap(g_fb_base, frame_buffer_size); // 释放显存映射
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close(fd_fb);
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return 0;
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}
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