From 7ac39b10f703838ce6770af5985c64e9621431e0 Mon Sep 17 00:00:00 2001
From: Peter Johnson <johnson.peter@gmail.com>
Date: Wed, 23 Dec 2020 13:05:25 -0800
Subject: [PATCH] [wpigui] Add icon support

---
 wpigui/src/main/native/cpp/wpigui.cpp         | 18 ++++++++++++++++
 wpigui/src/main/native/include/wpigui.h       | 21 +++++++++++++++++++
 .../src/main/native/include/wpigui_internal.h |  2 ++
 3 files changed, 41 insertions(+)

diff --git a/wpigui/src/main/native/cpp/wpigui.cpp b/wpigui/src/main/native/cpp/wpigui.cpp
index cbaa3b84fa..a1be20a32e 100644
--- a/wpigui/src/main/native/cpp/wpigui.cpp
+++ b/wpigui/src/main/native/cpp/wpigui.cpp
@@ -208,6 +208,14 @@ bool gui::Initialize(const char* title, int width, int height) {
   glfwSetWindowMaximizeCallback(gContext->window, WindowMaximizeCallback);
   glfwSetWindowPosCallback(gContext->window, WindowPosCallback);
 
+  // Set icons
+  if (!gContext->icons.empty()) {
+    glfwSetWindowIcon(gContext->window, gContext->icons.size(),
+                      gContext->icons.data());
+    for (auto&& icon : gContext->icons) stbi_image_free(icon.pixels);
+    gContext->icons.clear();
+  }
+
   // Setup Dear ImGui style
   SetStyle(static_cast<Style>(gContext->style));
 
@@ -304,6 +312,16 @@ void gui::AddLateExecute(std::function<void()> execute) {
 
 GLFWwindow* gui::GetSystemWindow() { return gContext->window; }
 
+bool gui::AddIcon(const unsigned char* data, int len) {
+  // Load from memory
+  GLFWimage image;
+  image.pixels =
+      stbi_load_from_memory(data, len, &image.width, &image.height, nullptr, 4);
+  if (!data) return false;
+  gContext->icons.emplace_back(std::move(image));
+  return true;
+}
+
 int gui::AddFont(
     const char* name,
     std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>
diff --git a/wpigui/src/main/native/include/wpigui.h b/wpigui/src/main/native/include/wpigui.h
index 8a9bb79c38..225975fc2e 100644
--- a/wpigui/src/main/native/include/wpigui.h
+++ b/wpigui/src/main/native/include/wpigui.h
@@ -12,6 +12,11 @@
 
 #include <imgui.h>
 
+#if __has_include(<wpi/StringRef.h>)
+#include <wpi/StringRef.h>
+#define WPIGUI_HAS_STRINGREF
+#endif
+
 extern "C" struct GLFWwindow;
 
 namespace wpi::gui {
@@ -86,6 +91,22 @@ void AddLateExecute(std::function<void()> execute);
  */
 GLFWwindow* GetSystemWindow();
 
+/**
+ * Adds an application icon.  Multiple icons (of different sizes) may be
+ * set.  This must be called prior to initialization to have an effect.
+ *
+ * @param data image data
+ * @param len image data length
+ * @return False if image data could not be read
+ */
+bool AddIcon(const unsigned char* data, int len);
+
+#ifdef WPIGUI_HAS_STRINGREF
+inline bool AddIcon(wpi::StringRef data) {
+  return AddIcon(data.bytes_begin(), data.size());
+}
+#endif
+
 /**
  * Adds a font to the GUI.  The passed function is called during
  * initialization as many times as necessary to create a range of sizes.
diff --git a/wpigui/src/main/native/include/wpigui_internal.h b/wpigui/src/main/native/include/wpigui_internal.h
index 8cbede0bdd..3fb16464d4 100644
--- a/wpigui/src/main/native/include/wpigui_internal.h
+++ b/wpigui/src/main/native/include/wpigui_internal.h
@@ -57,6 +57,8 @@ struct Context : public SavedSettings {
   int fontScale = 2;  // updated by main loop
   std::vector<Font> fonts;
 
+  std::vector<GLFWimage> icons;
+
   std::string iniPath = "imgui.ini";
 };