From fc7575b60ea5bc10ebab5209ba6db662b6a30a61 Mon Sep 17 00:00:00 2001
From: Jonathan Thomas <jonathan@openshot.org>
Date: Fri, 18 Nov 2022 00:32:48 -0600
Subject: [PATCH] Implementing a fix for mask contrast proposed by GitHub user
 xotmatrix

---
 src/effects/Mask.cpp | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/effects/Mask.cpp b/src/effects/Mask.cpp
index 2ad1987a..8cd71cee 100644
--- a/src/effects/Mask.cpp
+++ b/src/effects/Mask.cpp
@@ -114,11 +114,8 @@ std::shared_ptr<openshot::Frame> Mask::GetFrame(std::shared_ptr<openshot::Frame>
 		gray_value += (255 * brightness_value);
 
 		// Adjust the contrast
-		float factor = (259 * (contrast_value + 255)) / (255 * (259 - contrast_value));
-		gray_value = constrain((factor * (gray_value - 128)) + 128);
-
-		// Constrain the value from 0 to 255
-		gray_value = constrain(gray_value);
+		float factor = (20 / (20 - contrast_value));
+		gray_value = (factor * (gray_value - 128) + 128);
 
 		// Calculate the % change in alpha
 		float alpha_percent = float(constrain(A - gray_value)) / 255.0;