Add on-screen feedback for some keyboard shortcuts (so you know which setting was changed)

UI/OnScreenDisplay.cpp

@@ -0,0 +1,52 @@
+#include "UI/OnScreenDisplay.h"
+#include "UI/ui_atlas.h"
+
+#include "base/colorutil.h"
+#include "base/display.h"
+#include "base/timeutil.h"
+#include "gfx_es2/draw_buffer.h"
+
+OnScreenMessages osm;
+
+void OnScreenMessages::Draw(DrawBuffer &draw) {
+	// First, clean out old messages.
+	std::lock_guard<std::recursive_mutex> guard(mutex_);
+
+restart:
+	double now = time_now_d();
+	for (auto iter = messages_.begin(); iter != messages_.end(); iter++) {
+		if (iter->endTime < now) {
+			messages_.erase(iter);
+			goto restart;
+		}
+	}
+
+	// Get height
+	float w, h;
+	draw.MeasureText(UBUNTU24, "Wg", &w, &h);
+
+	float y = 10.0f;
+	// Then draw them all. 
+	for (auto iter = messages_.begin(); iter != messages_.end(); ++iter) {
+		float alpha = (iter->endTime - time_now_d()) * 4;
+		if (alpha > 1.0) alpha = 1.0;
+		if (alpha < 0.0) alpha = 0.0;
+		draw.DrawTextShadow(UBUNTU24, iter->text.c_str(), dp_xres / 2, y, colorAlpha(iter->color, alpha), ALIGN_TOP | ALIGN_HCENTER);
+		y += h;
+	}
+}
+
+void OnScreenMessages::Show(const std::string &message, float duration_s, uint32_t color, int icon) {
+	std::lock_guard<std::recursive_mutex> guard(mutex_);
+	double now = time_now_d();
+	Message msg;
+	msg.text = message;
+	msg.color = color;
+	msg.endTime = now + duration_s;
+	msg.icon = icon;
+	messages_.insert(messages_.begin(), msg);
+}
+
+void OnScreenMessages::ShowOnOff(const std::string &message, bool b, float duration_s, uint32_t color, int icon) {
+	Show(message + (b ? ": on" : ": off"), duration_s, color, icon);
+}