CODEWITHSUNDEEP
cimage-processingrgbgrayscalelibpng
Jav
Jav

Reputation: 1607

writing a PNG in grayscale or RGB in C with libpng

I'm trying to write a PNG file from an image that can be grayscale (8bits*1componant) or rgb (8bits*3componants) with libpng in C.

I read the manual and wrote this piece of code that doesn't work :-/

/* writing the image */
png_byte *row_pointers[img->height];
int h;
for (h = 0 ; h < img->height ; h++)
{
    row_pointers[h] = img->data+h*img->width*image_components;
}
png_write_image(png_ptr, row_pointers);

Nothing is written into the image, and I don't understand why.

img.data points to the image datas (interlaced in the case of RGB format)

Upvotes: 2

Views: 4679

Answers (1)

Emilien
Emilien

Reputation: 2445

The documentation says you are supposed to use png_write_end, see "Finishing a sequential write" section in http://www.libpng.org/pub/png/libpng-1.2.5-manual.html. There are plenty of examples out there (eg http://zarb.org/~gc/html/libpng.html)

Upvotes: 1

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