谁能帮忙写个ｐｎｇ图片旋转的程序啊，

[GarbageCan]

需要一个ＢＣＢ的图片旋转，位图旋转的不要，因为会有白色的背景，想要ｐｎｇ格式的图片旋转，网上也搜过，但是大部分是位图旋转，所以大佬谁能帮忙写几行代码讲解一下（代码有注释最好，那样我自己看就可以，就省得麻烦二次询问了），最简单能实现功能就好。提前谢谢各位了，手动抱拳！

[GarbageCan]

@侠客小贝 搞不出来，能不能直接写个简单的代码啊

[侠客小贝]

https://blog.csdn.net/weixin_33167915/article/details/117246159 这个网址应该能帮到你吧。

[侠客小贝]

这个代码基于OpenCV和C++底层实现的图片旋转

[日立奔腾浪潮微软松下联想]

你能不能直接修改zip中的文件内容而不解压~

[ooolinux]

TBitmap有32位模式，支持阿尔法通道，不过我没试过。

[侠客小贝]

旋转90度可以吗

[侠客小贝]

#include
#include <stdlib.h>
using namespace std;
void displayMatrix(unsigned int const *p, unsigned int row, unsigned int col);
void rotate(unsigned int *pS, unsigned int *pD, unsigned int row, unsigned int col);
int main()
{
// 声明
unsigned int image[][4] = {{1,2,3,4}, {5,6,7,8}, {9,10,11,12}};
unsigned int *pSource;
unsigned int *pDestination;
unsigned int m, n;
//设置初始值和内存分配
m = 3, n = 4, pSource = (unsigned int *)image;
pDestination = (unsigned int *)malloc(sizeof(int)mn);
// 处理每个缓冲区
displayMatrix(pSource, m, n);
rotate(pSource, pDestination, m, n);
displayMatrix(pDestination, n, m);
free(pDestination);
getchar();
return 0;
}
void displayMatrix(unsigned int const p, unsigned int r, unsigned int c)
{
unsigned int row, col;
cout<<"nn";
for(row = 0; row < r; row++)
{
for(col = 0; col < c; col++)
{
cout<<"t"<<(p + row * c + col);
}
cout<<"n";
}
cout<<"nn";
}
void rotate(unsigned int *pS, unsigned int *pD, unsigned int row, unsigned int col)
{
unsigned int r, c;
for(r = 0; r < row; r++)
{
for(c = 0; c < col; c++)
{
*(pD + c * row + (row - r - 1)) = *(pS + r * col + c);
}
}
}

[侠客小贝]

第一行是iostream

[侠客小贝]

#include <png.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

/* A coloured pixel. */

typedef struct
{
uint8_t red;
uint8_t green;
uint8_t blue;
}
pixel_t;

/* A picture. */

typedef struct
{
pixel_t *pixels;
size_t width;
size_t height;
}
bitmap_t;

/* Given "bitmap", this returns the pixel of bitmap at the point
("x", "y"). */

static pixel_t * pixel_at (bitmap_t * bitmap, int x, int y)
{
return bitmap->pixels + bitmap->width * y + x;
}

/* Write "bitmap" to a PNG file specified by "path"; returns 0 on
success, non-zero on error. */

static int save_png_to_file (bitmap_t *bitmap, const char path)
{
FILE * fp;
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
size_t x, y;
png_byte ** row_pointers = NULL;
/ "status" contains the return value of this function. At first
it is set to a value which means 'failure'. When the routine
has finished its work, it is set to a value which means
'success'. /
int status = -1;
/ The following number is set by trial and error only. I cannot
see where it it is documented in the libpng manual.
*/
int pixel_size = 3;
int depth = 8;

fp = fopen (path, "wb");
if (! fp) {
    goto fopen_failed;
}

png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (png_ptr == NULL) {
    goto png_create_write_struct_failed;
}

info_ptr = png_create_info_struct (png_ptr);
if (info_ptr == NULL) {
    goto png_create_info_struct_failed;
}

/* Set up error handling. */

if (setjmp (png_jmpbuf (png_ptr))) {
    goto png_failure;
}

/* Set image attributes. */

png_set_IHDR (png_ptr,
              info_ptr,
              bitmap->width,
              bitmap->height,
              depth,
              PNG_COLOR_TYPE_RGB,
              PNG_INTERLACE_NONE,
              PNG_COMPRESSION_TYPE_DEFAULT,
              PNG_FILTER_TYPE_DEFAULT);

/* Initialize rows of PNG. */

row_pointers = png_malloc (png_ptr, bitmap->height * sizeof (png_byte *));
for (y = 0; y < bitmap->height; y++) {
    png_byte *row = 
        png_malloc (png_ptr, sizeof (uint8_t) * bitmap->width * pixel_size);
    row_pointers[y] = row;
    for (x = 0; x < bitmap->width; x++) {
        pixel_t * pixel = pixel_at (bitmap, x, y);
        *row++ = pixel->red;
        *row++ = pixel->green;
        *row++ = pixel->blue;
    }
}

/* Write the image data to "fp". */

png_init_io (png_ptr, fp);
png_set_rows (png_ptr, info_ptr, row_pointers);
png_write_png (png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);

/* The routine has successfully written the file, so we set
   "status" to a value which indicates success. */

status = 0;

for (y = 0; y < bitmap->height; y++) {
    png_free (png_ptr, row_pointers[y]);
}
png_free (png_ptr, row_pointers);

png_failure:
png_create_info_struct_failed:
png_destroy_write_struct (&png_ptr, &info_ptr);
png_create_write_struct_failed:
fclose (fp);
fopen_failed:
return status;
}

/* Given "value" and "max", the maximum value which we expect "value"
to take, this returns an integer between 0 and 255 proportional to
"value" divided by "max". */

static int pix (int value, int max)
{
if (value < 0) {
return 0;
}
return (int) (256.0 *((double) (value)/(double) max));
}

int main ()
{
bitmap_t fruit;
int x;
int y;
int status;

status = 0;

/* Create an image. */

fruit.width = 100;
fruit.height = 100;

fruit.pixels = calloc (fruit.width * fruit.height, sizeof (pixel_t));

if (! fruit.pixels) {
return -1;
}

for (y = 0; y < fruit.height; y++) {
    for (x = 0; x < fruit.width; x++) {
        pixel_t * pixel = pixel_at (& fruit, x, y);
        pixel->red = pix (x, fruit.width);
        pixel->green = pix (y, fruit.height);
    }
}

/* Write the image to a file 'fruit.png'. */

if (save_png_to_file (& fruit, "fruit.png")) {
fprintf (stderr, "Error writing file.\n");
status = -1;
}

free (fruit.pixels);

return status;

}