JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

Question

Digital camera photos are often saved as JPEG with an EXIF \"orientation\" tag. To display correctly, images need to be rotated/mirrored depending on which orientation is se

Answer 1

If

width = img.width;
height = img.height;
var ctx = canvas.getContext('2d');

Then you can use these transformations to turn the image to orientation 1

From orientation:

1. ctx.transform(1, 0, 0, 1, 0, 0);
2. ctx.transform(-1, 0, 0, 1, width, 0);
3. ctx.transform(-1, 0, 0, -1, width, height);
4. ctx.transform(1, 0, 0, -1, 0, height);
5. ctx.transform(0, 1, 1, 0, 0, 0);
6. ctx.transform(0, 1, -1, 0, height, 0);
7. ctx.transform(0, -1, -1, 0, height, width);
8. ctx.transform(0, -1, 1, 0, 0, width);

Before drawing the image on ctx