add brightness and contrast (#396)

* Imlib2 supports modifying gamma, brightness and contrast directly
  while sxiv only supports gamma. Makes sense to extend it to brightness
  and contrast as well.

* Since color corrections need to be aware of each other, they have been
  refactored into one centralized function.

* This also makes the code more hackable as it makes it easier to add
  more color correction functions without them interfering with each
  other.

Co-authored-by: 0ion9 <finticemo@gmail.com>
Co-authored-by: NRK <nrk@disroot.org>
Reviewed-on: https://codeberg.org/nsxiv/nsxiv/pulls/396
Reviewed-by: NRK <nrk@disroot.org>
Reviewed-by: TAAPArthur <taaparthur@noreply.codeberg.org>
Co-authored-by: Berke Kocaoğlu <kberke@metu.edu.tr>
Co-committed-by: Berke Kocaoğlu <kberke@metu.edu.tr>

1 files changed, 4 insertions, 0 deletions

diff --git a/main.c b/main.c
index 44f8eb9..8ee5b9d 100644
--- a/main.c
+++ b/main.c
@@ -444,6 +444,10 @@ static void update_info(void)
 		}
 		if (img.gamma)
 			bar_put(r, "G%+d" BAR_SEP, img.gamma);
+		if (img.brightness)
+			bar_put(r, "B%+d" BAR_SEP, img.brightness);
+		if (img.contrast)
+			bar_put(r, "C%+d" BAR_SEP, img.contrast);
 		bar_put(r, "%3d%%" BAR_SEP, (int) (img.zoom * 100.0));
 		if (img.multi.cnt > 0) {
 			for (fn = 0, i = img.multi.cnt; i > 0; fn++, i /= 10);