From f5d80aa46f100a5fd76955998341fad7c3f42a47 Mon Sep 17 00:00:00 2001
From: Henrik Hautakoski <henrik.hautakoski@gmail.com>
Date: Tue, 27 Oct 2020 17:04:10 +0100
Subject: [PATCH] Platform/Unix/X11Display: Implement setIcon()

---
 source/Platform/Unix/X11Display.cpp | 35 ++++++++++++++++++++++++++++-
 source/Platform/Unix/X11Display.h   |  3 +++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/source/Platform/Unix/X11Display.cpp b/source/Platform/Unix/X11Display.cpp
index 968a9c3..94cea38 100644
--- a/source/Platform/Unix/X11Display.cpp
+++ b/source/Platform/Unix/X11Display.cpp
@@ -1,6 +1,7 @@
 
 #include <Spectre/Display/DisplayDescription.h> // Prevents conflict with X.h defining "None"
 #include <Spectre/System/Log.h>
+#include <Spectre/Graphics/Image.h>
 #include "X11WindowEventHandler.h"
 #include "X11SharedDisplay.h"
 #include "GLXContext.h"
@@ -116,9 +117,41 @@ void X11Display::setCaption(const std::string& caption)
 	::XStoreName(m_disp, m_win, caption.c_str());
 }
 
+// TODO: Move this up to the non-platform layer.
 void X11Display::setIcon(const std::string& icon)
 {
-	// TODO: Implement
+	Image img;
+
+	if (img.loadFromFile(icon)) {
+		setIcon(img.getWidth(), img.getHeight(), img.getPixels());
+	}
+}
+
+void X11Display::setIcon(unsigned int width, unsigned int height, const uint8_t *pixels)
+{
+	::Atom net_wm_icon = getAtom("_NET_WM_ICON", False);
+    ::Atom cardinal = getAtom("CARDINAL", False);
+	std::vector<uint64_t> buffer(2 + width * height);
+	uint64_t *ptr = &buffer[0];
+
+	*ptr++ = width;
+	*ptr++ = height;
+
+	// TODO: Conversion between differnet formats should be defined as functions in Graphics/PixelFormat.h
+	for (std::size_t i = 0; i < width * height; i++) {
+		*ptr++ =  (pixels[i * 4 + 2] << 0)
+				| (pixels[i * 4 + 1] << 8)
+				| (pixels[i * 4 + 0] << 16)
+				| (pixels[i * 4 + 3] << 24);
+	}
+
+	::XChangeProperty(m_disp, m_win,
+		net_wm_icon, cardinal, 32,
+		PropModeReplace,
+		reinterpret_cast<const unsigned char*>(&buffer[0]),
+		2 + width * height);
+
+	XFlush(m_disp);
 }
 
 void X11Display::createHiddenCursor()
diff --git a/source/Platform/Unix/X11Display.h b/source/Platform/Unix/X11Display.h
index ec4c094..538e5c0 100644
--- a/source/Platform/Unix/X11Display.h
+++ b/source/Platform/Unix/X11Display.h
@@ -6,6 +6,7 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/Xos.h>
+#include <cstdint>
 #include <Platform/PlatformDisplay.h>
 
 namespace sp {
@@ -35,6 +36,8 @@ public :
 
 	virtual void 	setIcon(const std::string& icon);
 
+	virtual void	setIcon(unsigned int width, unsigned int height, const uint8_t *pixels);
+
 	virtual void	showCursor(bool value);
 
 	void 			processEvent(const ::XEvent& event);