From b45cadb0654ce47dea0d24046110820b9ce8ae99 Mon Sep 17 00:00:00 2001
From: Eugene Sandulenko
Date: Tue, 1 Jan 2019 23:06:35 +0100
Subject: GRAPHICS: Enhanced setAlpha method

---
 graphics/transparent_surface.cpp | 6 ++++--
 graphics/transparent_surface.h   | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

(limited to 'graphics')

diff --git a/graphics/transparent_surface.cpp b/graphics/transparent_surface.cpp
index a24f7198aa..eb8d3fe5ce 100644
--- a/graphics/transparent_surface.cpp
+++ b/graphics/transparent_surface.cpp
@@ -719,15 +719,17 @@ void TransparentSurface::applyColorKey(uint8 rKey, uint8 gKey, uint8 bKey, bool
 /**
  * Sets alpha channel for all pixels to specified value
  * @param alpha  value of the alpha channel to set
+ * @param skipTransparent  if set to true, then do not touch pixels with alpha=0
  */
-void TransparentSurface::setAlpha(uint8 alpha) {
+void TransparentSurface::setAlpha(uint8 alpha, bool skipTransparent) {
 	assert(format.bytesPerPixel == 4);
 	for (int i = 0; i < h; i++) {
 		for (int j = 0; j < w; j++) {
 			uint32 pix = ((uint32 *)pixels)[i * w + j];
 			uint8 r, g, b, a;
 			format.colorToARGB(pix, a, r, g, b);
-			a = alpha;
+			if (!skipTransparent || a)
+				a = alpha;
 			((uint32 *)pixels)[i * w + j] = format.ARGBToColor(a, r, g, b);
 		}
 	}
diff --git a/graphics/transparent_surface.h b/graphics/transparent_surface.h
index 0738c90f90..8f4493679b 100644
--- a/graphics/transparent_surface.h
+++ b/graphics/transparent_surface.h
@@ -137,7 +137,7 @@ struct TransparentSurface : public Graphics::Surface {
 						TSpriteBlendMode blend = BLEND_NORMAL);
 
 	void applyColorKey(uint8 r, uint8 g, uint8 b, bool overwriteAlpha = false);
-	void setAlpha(uint8 alpha);
+	void setAlpha(uint8 alpha, bool skipTransparent = false);
 
 	/**
 	 * @brief Scale function; this returns a transformed version of this surface after rotation and
-- 
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