调整图像大小不受支持的文件格式 [英] Resize image unsupported file format
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问题描述
我应该用整数n(1和100之间)调整bmp的大小。
我目前没有任何编译错误或内存泄漏。
输出是错误的。
我会得到空白的bmp图像(虽然已调整大小)。
我也得到:
I am supposed to resize a bmp by the integer n ( betw 1 and 100).
I currently don't have any compilation errors or memory leaks.
The output would be wrong.
I would get blank bmp images (that are resized, though).
I also get:
~/workspace/pset4/bmp/ $ ./resize 3 small.bmp large.bmp
*** Error in `./resize': double free or corruption (top): 0x000000000125c250 ***
Aborted
非常感谢,c
我尝试了什么: < br $>
Thanks a lot,c
What I have tried:
int main(int argc, char* argv[])
{
int n;
// ensure proper usage
if (argc != 4)
{
printf("Usage: ./resize n infile outfile\n");
return 1;
}
else
{
n = atoi(argv[1]);
if ( ( n < 0 ) || ( n > 100 ) )
{
printf(" n must be a positive floating integer from 0.0 up till 100.0\n");
return 1;
}
}
// remember filenames
char* infile = argv[2];
char* outfile = argv[3];
// open input file
FILE* input = fopen(infile, "r");
if (input == NULL)
{
printf("Could not open %s.\n", infile);
return 2;
}
// open output file
FILE* output = fopen(outfile, "w");
if (output == NULL)
{
fclose(input);
fprintf(stderr, "Could not create %s.\n", outfile);
return 3;
}
// read infile's BITMAPFILEHEADER
BITMAPFILEHEADER bf;
fread(&bf, sizeof(BITMAPFILEHEADER), 1, input);
// read infile's BITMAPINFOHEADER
BITMAPINFOHEADER bi;
fread(&bi, sizeof(BITMAPINFOHEADER), 1, input);
// ensure infile is (likely) a 24-bit uncompressed BMP 4.0
if (bf.bfType != 0x4d42 || bf.bfOffBits != 54 || bi.biSize != 40 ||
bi.biBitCount != 24 || bi.biCompression != 0)
{
fclose(output);
fclose(input);
fprintf(stderr, "Unsupported file format.\n");
return 4;
}
int originalwidth = bi.biWidth;
int originalheight = bi.biHeight;
int originalpadding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biWidth = bi.biWidth * n;
bi.biHeight = bi.biHeight * n;
int newpadding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biSizeImage = bi.biHeight * ( 3 * bi.biWidth + newpadding );
bf.bfSize = bf.bfOffBits + bi.biSizeImage;
// write outfile's BITMAPFILEHEADER
fwrite(&bf, sizeof(BITMAPFILEHEADER), 1, output);
// write outfile's BITMAPINFOHEADER
fwrite(&bi, sizeof(BITMAPINFOHEADER), 1, output);
// iterate over infile's scanlines
for (int i = 0; i < abs(originalheight); i++)
{
int numberoflines = 0;
// iterate over pixels in scanline
for (int j = 0; j < abs(originalwidth); j++)
{
// temporary storage
RGBTRIPLE triple;
// read RGB triple from infile
fread(&triple, sizeof(RGBTRIPLE), 1, input);
// write RGB triple to outfile n times for horizontal resize
for (int a = 0; a < n; a++)
{
fwrite(&triple, sizeof(RGBTRIPLE), 1, output);
fclose(output);
//temporary = malloc(sizeof(RGBTRIPLE));
//temporary = fopen("tempmem.txt", "w");
//fwrite(&triple, sizeof(RGBTRIPLE), 1, temporary);
}
//for (int b = 0; b < n-1; b++)
//{
//fwrite(temporary, sizeof(RGBTRIPLE),1, output);
//}
}
// skip over padding, if any
fseek( input, newpadding, SEEK_CUR);
// then add it back (to demonstrate how)
for (int k = 0; k < newpadding; k++)
{
fputc(0x00, output);
}
if ( numberoflines < n - 1)
{
fseek( input, -1 * ( 3 * originalwidth + originalpadding ), SEEK_CUR);
}
numberoflines++;
}
// close infile
//fclose( temporary);
fclose(input);
// close outfile
fclose(output);
// that's all folks
return 0;
}
推荐答案
./ resize 3 small.bmp large.bmp
***错误。 / resize':double free或corruption(top):0x000000000125c250 ***
Aborted
./resize 3 small.bmp large.bmp *** Error in `./resize': double free or corruption (top): 0x000000000125c250 *** Aborted
非常感谢,c
我尝试过:
Thanks a lot,c
What I have tried:
int main(int argc, char* argv[])
{
int n;
// ensure proper usage
if (argc != 4)
{
printf("Usage: ./resize n infile outfile\n");
return 1;
}
else
{
n = atoi(argv[1]);
if ( ( n < 0 ) || ( n > 100 ) )
{
printf(" n must be a positive floating integer from 0.0 up till 100.0\n");
return 1;
}
}
// remember filenames
char* infile = argv[2];
char* outfile = argv[3];
// open input file
FILE* input = fopen(infile, "r");
if (input == NULL)
{
printf("Could not open %s.\n", infile);
return 2;
}
// open output file
FILE* output = fopen(outfile, "w");
if (output == NULL)
{
fclose(input);
fprintf(stderr, "Could not create %s.\n", outfile);
return 3;
}
// read infile's BITMAPFILEHEADER
BITMAPFILEHEADER bf;
fread(&bf, sizeof(BITMAPFILEHEADER), 1, input);
// read infile's BITMAPINFOHEADER
BITMAPINFOHEADER bi;
fread(&bi, sizeof(BITMAPINFOHEADER), 1, input);
// ensure infile is (likely) a 24-bit uncompressed BMP 4.0
if (bf.bfType != 0x4d42 || bf.bfOffBits != 54 || bi.biSize != 40 ||
bi.biBitCount != 24 || bi.biCompression != 0)
{
fclose(output);
fclose(input);
fprintf(stderr, "Unsupported file format.\n");
return 4;
}
int originalwidth = bi.biWidth;
int originalheight = bi.biHeight;
int originalpadding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biWidth = bi.biWidth * n;
bi.biHeight = bi.biHeight * n;
int newpadding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biSizeImage = bi.biHeight * ( 3 * bi.biWidth + newpadding );
bf.bfSize = bf.bfOffBits + bi.biSizeImage;
// write outfile's BITMAPFILEHEADER
fwrite(&bf, sizeof(BITMAPFILEHEADER), 1, output);
// write outfile's BITMAPINFOHEADER
fwrite(&bi, sizeof(BITMAPINFOHEADER), 1, output);
// iterate over infile's scanlines
for (int i = 0; i < abs(originalheight); i++)
{
int numberoflines = 0;
// iterate over pixels in scanline
for (int j = 0; j < abs(originalwidth); j++)
{
// temporary storage
RGBTRIPLE triple;
// read RGB triple from infile
fread(&triple, sizeof(RGBTRIPLE), 1, input);
// write RGB triple to outfile n times for horizontal resize
for (int a = 0; a < n; a++)
{
fwrite(&triple, sizeof(RGBTRIPLE), 1, output);
fclose(output);
//temporary = malloc(sizeof(RGBTRIPLE));
//temporary = fopen("tempmem.txt", "w");
//fwrite(&triple, sizeof(RGBTRIPLE), 1, temporary);
}
//for (int b = 0; b < n-1; b++)
//{
//fwrite(temporary, sizeof(RGBTRIPLE),1, output);
//}
}
// skip over padding, if any
fseek( input, newpadding, SEEK_CUR);
// then add it back (to demonstrate how)
for (int k = 0; k < newpadding; k++)
{
fputc(0x00, output);
}
if ( numberoflines < n - 1)
{
fseek( input, -1 * ( 3 * originalwidth + originalpadding ), SEEK_CUR);
}
numberoflines++;
}
// close infile
//fclose( temporary);
fclose(input);
// close outfile
fclose(output);
// that's all folks
return 0;
}
我假设你使用的是Windows。然后应该以二进制模式打开文件以禁用换行符:
I assume that you are using Windows. Then the files should be opened in binary mode to disable newline translation:
FILE* input = fopen(infile, "rb");
FILE* output = fopen(outfile, "wb");
这里你应该使用输入的填充:
Here you should use the padding of the input:
// skip over padding, if any
// Your code:
//fseek( input, newpadding, SEEK_CUR);
// Should be:
fseek( input, originalpadding, SEEK_CUR);
但是最重要的错误导致错误消息在这里:
But the most important error resulting in the error message is here:
// write RGB triple to outfile n times for horizontal resize
for (int a = 0; a < n; a++)
{
fwrite(&triple, sizeof(RGBTRIPLE), 1, output);
fclose(output);
}
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