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我已經發現堆棧溢出代碼來做到這一點,但我有一些使用它的錯誤。我不確定我做錯了什麼,因爲我沒有太多的ppm文件經驗。謝謝大家的幫助。閱讀更改和打印PPM圖像
typedef struct {
int x, y;
PPMPixel *data;
} PPMImage;
#define CREATOR "RPFELGUEIRAS"
#define RGB_COMPONENT_COLOR 255
static PPMImage *readPPM(const char *filename = "ukraine.ppm")
{
char buff[16];
PPMImage *img;
FILE *fp;
int c, rgb_comp_color;
//open PPM file for reading
fp = fopen("ukraine.ppm", "rb");
if (!fp) {
fprintf(stderr, "Unable to open file '%s'\n", filename);
exit(1);
}
//read image format
if (!fgets(buff, sizeof(buff), fp)) {
perror(ukraine.ppm);
exit(1);
}
//check the image format
if (buff[0] != 'P' || buff[1] != '6') {
fprintf(stderr, "Invalid image format (must be 'P6')\n");
exit(1);
}
//alloc memory form image
img = (PPMImage *)malloc(sizeof(PPMImage));
if (!img) {
fprintf(stderr, "Unable to allocate memory\n");
exit(1);
}
//check for comments
c = getc(fp);
while (c == '#') {
while (getc(fp) != '\n') ;
c = getc(fp);
}
ungetc(c, fp);
//read image size information
if (fscanf(fp, "%d %d", &img->x, &img->y) != 2) {
fprintf(stderr, "Invalid image size (error loading '%s')\n", ukraine.ppm);
exit(1);
}
//read rgb component
if (fscanf(fp, "%d", &rgb_comp_color) != 1) {
fprintf(stderr, "Invalid rgb component (error loading '%s')\n", filename);
exit(1);
}
//check rgb component depth
if (rgb_comp_color!= RGB_COMPONENT_COLOR) {
fprintf(stderr, "'%s' does not have 8-bits components\n", filename);
exit(1);
}
while (fgetc(fp) != '\n') ;
//memory allocation for pixel data
img->data = (PPMPixel*)malloc(img->x * img->y * sizeof(PPMPixel));
if (!img) {
fprintf(stderr, "Unable to allocate memory\n");
exit(1);
}
//read pixel data from file
if (fread(img->data, 3 * img->x, img->y, fp) != img->y) {
fprintf(stderr, "Error loading image '%s'\n", filename);
exit(1);
}
fclose(fp);
return img;
}
void writePPM(const char *filename = "ukraine.ppm", PPMImage *img)
{
FILE *fp;
//open file for output
fp = fopen(ukraine.ppm, "wb");
if (!fp) {
fprintf(stderr, "Unable to open file '%s'\n",filename);
exit(1);
}
//write the header file
//image format
fprintf(fp, "P6\n");
//comments
fprintf(fp, "# Created by %s\n",CREATOR);
//image size
fprintf(fp, "%d %d\n",img->x,img->y);
// rgb component depth
fprintf(fp, "%d\n",RGB_COMPONENT_COLOR);
// pixel data
fwrite(img->data, 3 * img->x, img->y, fp);
fclose(fp);
}
void changeColorPPM(PPMImage *img)
{
int i;
if(img){
for(i=0;i<img->x*img->y;i++){
img->data[i].red=RGB_COMPONENT_COLOR-img->data[i].red;
img->data[i].green=RGB_COMPONENT_COLOR-img->data[i].green;
img->data[i].blue=RGB_COMPONENT_COLOR-img->data[i].blue;
}
}
}
int main(){
PPMImage *image;
image = readPPM("can_bottom.ppm");
changeColorPPM(image);
writePPM("can_bottom2.ppm",image);
printf("Press any key...");
getchar();
return(0);
}
錯誤消息
[21:47:34] [email protected]:~/101/lab12 [8] gcc imageChange.c imageChange.c:18:47: error: expected â;â, â,â or â)â before â=â token
imageChange.c:94:36: error: expected â;â, â,â or â)â before â=â token
imageChange.c: In function âmainâ: imageChange.c:137:11: warning: assignment makes pointer from integer without a cast [enabled by default]
[21:47:34] [email protected]:~/101/lab12 [9] Last login: Tue Apr 14 21:28:19 2015 from 48.253.21.198.tigernet.wifi.dyn.clemson.edu
[23:42:52] [email protected]:~ [1]`
你錯過了幾個字符串的引號。看起來好像你要傳遞一個文件名參數,你應該使用它。您也不能有一個默認參數,後跟一個非默認參數。這些問題都不是PPM問題,它們只是不正確的C. –
以避免混淆,請在每個開口大括號'{「之後縮進(比如說4個)空格,並且在每個大括號之前取消縮進}}使用此一致縮進甚至如果大括號不包括'if','do','while','else'聲明 – user3629249
這是第18行?這是一般的行137? – user3629249