From 9751710eac4c4da6c4eb4f2840390298924e0806 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sat, 18 Feb 2012 12:21:12 +0100
Subject: [PATCH 1/1] Fix the rotatescreen fading so subpixel LCD works again.
 Generally a lot fewer hacks here.

---
 bigscreen/rotatescreen.cpp | 50 +++++++++++++++-----------------------
 bigscreen/rotatescreen.h   |  2 +-
 2 files changed, 21 insertions(+), 31 deletions(-)

diff --git a/bigscreen/rotatescreen.cpp b/bigscreen/rotatescreen.cpp
index 64e7269..655c7c3 100644
--- a/bigscreen/rotatescreen.cpp
+++ b/bigscreen/rotatescreen.cpp
@@ -40,6 +40,9 @@ void RotateScreen::draw(unsigned char *buf, unsigned width, unsigned height)
 		fadefrom_buf = new unsigned char[width * height * 4];
 	}
 	for (std::vector<Subscreen>::iterator i = subscreens.begin(); i != subscreens.end(); ++i) {
+		if (i->redbuf == NULL) {
+			i->redbuf = new unsigned char[width * height * 4];
+		}
 		if (i->buf == NULL) {
 			i->buf = new unsigned char[width * height * 4];
 			i->screen->draw(i->buf, width, height);
@@ -71,50 +74,33 @@ void RotateScreen::draw(unsigned char *buf, unsigned width, unsigned height)
 		if (elapsed_fade > 5.5 || (!fade_to_new_info && elapsed_fade > 0.5)) {
 			in_fade = false;
 
-			// set G&B to be = R
-			unsigned char *ptr = subscreens[current_screen].buf;
-			for (unsigned i = 0; i < width * height; ++i) {
-				ptr[1] = ptr[2] = ptr[3] = ptr[0];
-				ptr += 4;
-			}
-			
 			memcpy(buf, subscreens[current_screen].buf, width * height * 4);
 		} else {
-			// find the fade f
+			unsigned char *sptr1, *sptr2;
+			unsigned char *dptr = buf;
 			int f;
 			if (fade_to_new_info) {
 				if (elapsed_fade < 0.5) {
+					sptr1 = fadefrom_buf;
+					sptr2 = subscreens[current_screen].redbuf;
 					f = unsigned(elapsed_fade/0.5 * 256.0);
 				} else {
+					sptr1 = subscreens[current_screen].redbuf;
+					sptr2 = subscreens[current_screen].buf;
 					f = unsigned((elapsed_fade-0.5)/5.0 * 256.0);
 				}
 			} else {
+				sptr1 = fadefrom_buf;
+				sptr2 = subscreens[current_screen].buf;
 				f = unsigned(elapsed_fade/0.5 * 256.0);
 			}
 
-			unsigned char *sptr1 = fadefrom_buf;
-			unsigned char *sptr2 = subscreens[current_screen].buf;
-			unsigned char *dptr = buf;
-
-			if (fade_to_new_info && elapsed_fade >= 0.5) {
-				// fade G&B to be = R
-				for (unsigned i = 0; i < width * height; ++i) {
-					dptr[0] = sptr2[0] + (((int(sptr2[2]) - int(sptr2[0])) * f) >> 8);
-					dptr[1] = dptr[0];
-					dptr[2] = sptr2[2];
-					dptr[3] = sptr2[3];
-
-					sptr1 += 4, sptr2 += 4, dptr += 4;
-				}
-			} else {
-				for (unsigned i = 0; i < width * height; ++i) {
-					dptr[0] = sptr1[0] + (((int(sptr2[0]) - int(sptr1[0])) * f) >> 8);
-					dptr[1] = dptr[0];
-					dptr[2] = dptr[0];
-					dptr[3] = dptr[0];
+			for (unsigned i = 0; i < width * height; ++i) {
+				dptr[0] = sptr1[0] + (((int(sptr2[0]) - int(sptr1[0])) * f) >> 8);
+				dptr[1] = sptr1[1] + (((int(sptr2[1]) - int(sptr1[1])) * f) >> 8);
+				dptr[2] = sptr1[2] + (((int(sptr2[2]) - int(sptr1[2])) * f) >> 8);
 
-					sptr1 += 4, sptr2 += 4, dptr += 4;
-				}
+				sptr1 += 4, sptr2 += 4, dptr += 4;
 			}
 		}
 	} else {
@@ -147,6 +133,9 @@ void RotateScreen::draw(unsigned char *buf, unsigned width, unsigned height)
 			memcpy(fadefrom_buf, subscreens[old_current_screen].buf, width * height * 4);
 
 			if (subscreens[current_screen].screen->check_invalidated()) {
+				if (fade_to_new_info) {
+					subscreens[current_screen].screen->draw(subscreens[current_screen].redbuf, width, height);
+				}
 				subscreens[current_screen].screen->draw(subscreens[current_screen].buf, width, height);
 			}
 		}
@@ -196,6 +185,7 @@ bool RotateScreen::can_update()
 void RotateScreen::add_screen(GenericScreen *screen)
 {
 	Subscreen ss;
+	ss.redbuf = NULL;
 	ss.buf = NULL;
 	ss.screen = screen;
 
diff --git a/bigscreen/rotatescreen.h b/bigscreen/rotatescreen.h
index 6f53e24..6499912 100644
--- a/bigscreen/rotatescreen.h
+++ b/bigscreen/rotatescreen.h
@@ -11,7 +11,7 @@
  * one at a time). :-)
  */
 struct Subscreen {
-	unsigned char *buf;
+	unsigned char *redbuf, *buf;
 	GenericScreen *screen;
 };
 
-- 
2.39.2