Commented samples and shuffled bits of the initialisation based on user's feedback.

Clarifying C++
Added item in todo list

.gitignore

@@ -0,0 +1,14 @@
+## Visual Studio files
+examples/directx9_example/Debug/*
+examples/directx9_example/Release/*
+examples/directx9_example/ipch/*
+examples/opengl_example/Debug/*
+examples/opengl_example/Release/*
+examples/opengl_example/ipch/*
+*.opensdf
+*.sdf
+*.suo
+*.vcxproj.user
+
+## Ini files
+imgui.ini

README.md

@@ -1,7 +1,7 @@
 ImGui
 =====
 
-ImGui is a bloat-free graphical user interface library for C/C++. It is portable, renderer agnostic and carries minimal amount of dependencies (only 3 files are needed). It is based on an "immediate" graphical user interface paradigm which allows you to build simple user interfaces with ease.
+ImGui is a bloat-free graphical user interface library for C++. It is portable, renderer agnostic and carries minimal amount of dependencies (only 3 files are needed). It is based on an "immediate" graphical user interface paradigm which allows you to build simple user interfaces with ease.
 
 ImGui is designed to allow programmers to create "content creation" or "debug" tools (as opposed to tools for the average end-user). It favors simplicity and thus lacks certain features normally found in more high-level libraries, such as string localisation.
 

examples/directx9_example/main.cpp

@@ -203,17 +203,6 @@ HRESULT InitD3D(HWND hWnd)
     if (g_pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd, D3DCREATE_HARDWARE_VERTEXPROCESSING, &d3dpp, &g_pd3dDevice) < 0)
         return E_FAIL;
 
-	// Create the vertex buffer.
-	if (g_pd3dDevice->CreateVertexBuffer(10000 * sizeof(CUSTOMVERTEX), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &g_pVB, NULL) < 0)
-        return E_FAIL;
-
-	// Load font texture
-	const void* png_data;
-	unsigned int png_size;
-	ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
-	if (D3DXCreateTextureFromFileInMemory(g_pd3dDevice, png_data, png_size, &g_pTexture) < 0)
-		return E_FAIL;
-
     return S_OK;
 }
 
@@ -247,9 +236,11 @@ LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
 		io.MouseDown[1] = false; 
 		return true;
 	case WM_MOUSEWHEEL:
+		// Mouse wheel: -1,0,+1
 		io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1 : -1;
 		return true;
 	case WM_MOUSEMOVE:
+		// Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
 		io.MousePos.x = (signed short)(lParam);
 		io.MousePos.y = (signed short)(lParam >> 16); 
 		return true;
@@ -274,9 +265,10 @@ void InitImGui()
 	GetClientRect(hWnd, &rect);
 
 	ImGuiIO& io = ImGui::GetIO();
-	io.DisplaySize = ImVec2((float)(rect.right - rect.left), (float)(rect.bottom - rect.top));
+	io.DisplaySize = ImVec2((float)(rect.right - rect.left), (float)(rect.bottom - rect.top));	// Display size, in pixels. For clamping windows positions.
-	io.DeltaTime = 1.0f/60.0f;
+	io.DeltaTime = 1.0f/60.0f;																	// Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable)
-	io.KeyMap[ImGuiKey_Tab] = VK_TAB;
+	io.PixelCenterOffset = 0.0f;																// Align Direct3D Texels
+	io.KeyMap[ImGuiKey_Tab] = VK_TAB;															// Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array that we will update during the application lifetime.
 	io.KeyMap[ImGuiKey_LeftArrow] = VK_LEFT;
 	io.KeyMap[ImGuiKey_RightArrow] = VK_RIGHT;
 	io.KeyMap[ImGuiKey_UpArrow] = VK_UP;
@@ -297,6 +289,24 @@ void InitImGui()
 	io.RenderDrawListsFn = ImImpl_RenderDrawLists;
 	io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
 	io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
+
+	
+	// Create the vertex buffer
+	if (g_pd3dDevice->CreateVertexBuffer(10000 * sizeof(CUSTOMVERTEX), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &g_pVB, NULL) < 0)
+	{
+		IM_ASSERT(0);
+		return;
+	}
+
+	// Load font texture
+	const void* png_data;
+	unsigned int png_size;
+	ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
+	if (D3DXCreateTextureFromFileInMemory(g_pd3dDevice, png_data, png_size, &g_pTexture) < 0)
+	{
+		IM_ASSERT(0);
+		return;
+	}
 }
 
 int WINAPI wWinMain(HINSTANCE hInst, HINSTANCE, LPWSTR, int)

examples/opengl_example/main.cpp

@@ -217,13 +217,50 @@ void InitGL()
 	glewInit();
 
 	GLenum err = GL_NO_ERROR;
+	err = glGetError(); IM_ASSERT(err == GL_NO_ERROR);
+}
+
+void InitImGui()
+{
+	int w, h;
+	glfwGetWindowSize(window, &w, &h);
+
+	ImGuiIO& io = ImGui::GetIO();
+	io.DisplaySize = ImVec2((float)w, (float)h);			// Display size, in pixels. For clamping windows positions.
+	io.DeltaTime = 1.0f/60.0f;								// Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable)
+	io.PixelCenterOffset = 0.5f;							// Align OpenGL texels
+	io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB;					// Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array that we will update during the application lifetime.
+	io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
+	io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
+	io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
+	io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
+	io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
+	io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
+	io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
+	io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
+	io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
+	io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
+	io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
+	io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
+	io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
+	io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
+	io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
+	io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
+
+	io.RenderDrawListsFn = ImImpl_RenderDrawLists;
+	io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
+	io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
+
+
+	// Setup graphics backend
 	GLint status = GL_TRUE;
+	GLenum err = GL_NO_ERROR;
 	err = glGetError(); IM_ASSERT(err == GL_NO_ERROR);
 
-    // Create and compile the vertex shader
+	// Create and compile the vertex shader
-    vertexShader = glCreateShader(GL_VERTEX_SHADER);
+	vertexShader = glCreateShader(GL_VERTEX_SHADER);
-    glShaderSource(vertexShader, 1, &vertexSource, NULL);
+	glShaderSource(vertexShader, 1, &vertexSource, NULL);
-    glCompileShader(vertexShader);
+	glCompileShader(vertexShader);
 	glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
 	if (status != GL_TRUE)
 	{
@@ -233,19 +270,19 @@ void InitGL()
 		IM_ASSERT(status == GL_TRUE);
 	}
 
-    // Create and compile the fragment shader
+	// Create and compile the fragment shader
-    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+	fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
-    glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
+	glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
-    glCompileShader(fragmentShader);
+	glCompileShader(fragmentShader);
 	glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
 	IM_ASSERT(status == GL_TRUE);
 
-    // Link the vertex and fragment shader into a shader program
+	// Link the vertex and fragment shader into a shader program
-    shaderProgram = glCreateProgram();
+	shaderProgram = glCreateProgram();
-    glAttachShader(shaderProgram, vertexShader);
+	glAttachShader(shaderProgram, vertexShader);
-    glAttachShader(shaderProgram, fragmentShader);
+	glAttachShader(shaderProgram, fragmentShader);
-    glBindFragDataLocation(shaderProgram, 0, "o_col");
+	glBindFragDataLocation(shaderProgram, 0, "o_col");
-    glLinkProgram(shaderProgram);
+	glLinkProgram(shaderProgram);
 	glGetProgramiv(shaderProgram, GL_LINK_STATUS, &status);
 	IM_ASSERT(status == GL_TRUE);
 
@@ -270,37 +307,6 @@ void InitGL()
 	glVertexAttribPointer(colAttrib, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (void*)(4*sizeof(float)));
 	glEnableVertexAttribArray(colAttrib);
 	err = glGetError(); IM_ASSERT(err == GL_NO_ERROR);
-}
-
-void InitImGui()
-{
-	int w, h;
-	glfwGetWindowSize(window, &w, &h);
-
-	ImGuiIO& io = ImGui::GetIO();
-	io.DisplaySize = ImVec2((float)w, (float)h);
-	io.DeltaTime = 1.0f/60.0f;
-	io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB;
-	io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
-	io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
-	io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
-	io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
-	io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
-	io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
-	io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
-	io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
-	io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
-	io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
-	io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
-	io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
-	io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
-	io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
-	io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
-	io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
-
-	io.RenderDrawListsFn = ImImpl_RenderDrawLists;
-	io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
-	io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
 
 	// Load font texture
 	glGenTextures(1, &fontTex);
@@ -347,10 +353,10 @@ int main(int argc, char** argv)
 		time = current_time;
 		double mouse_x, mouse_y;
 		glfwGetCursorPos(window, &mouse_x, &mouse_y);
-		io.MousePos = ImVec2((float)mouse_x, (float)mouse_y);
+		io.MousePos = ImVec2((float)mouse_x, (float)mouse_y);							// Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
 		io.MouseDown[0] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0;
 		io.MouseDown[1] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;
-		io.MouseWheel = (mouse_wheel != 0) ? mouse_wheel > 0.0f ? 1 : - 1 : 0;
+		io.MouseWheel = (mouse_wheel != 0) ? mouse_wheel > 0.0f ? 1 : - 1 : 0;			// Mouse wheel: -1,0,+1
 		mouse_wheel = 0.0f;
 		ImGui::NewFrame();
 

imgui.cpp

@@ -144,6 +144,7 @@
  - filters: handle wildcards (with implicit leading/trailing *), regexps
  - shortcuts: add a shortcut api, e.g. parse "&Save" and/or "Save (CTRL+S)", pass in to widgets or provide simple ways to use (button=activate, input=focus)
  - keyboard: full keyboard navigation and focus
+ - clipboard: add a default "local" implementation of clipboard functions (user will only need to override them to connect to OS clipboard)
  - misc: not thread-safe
  - optimisation/render: use indexed rendering
  - optimisation/render: move clip-rect to vertex data? would allow merging all commands
@@ -156,8 +157,10 @@
 */
 
 #include "imgui.h"
-#include <ctype.h>
+#include <ctype.h>		// toupper
+#include <limits.h>		// INT_MAX
 #include <math.h>		// sqrt
+#include <stdint.h>		// intptr_t
 #include <stdio.h>		// vsnprintf
 #include <string.h>		// memset
 
@@ -259,6 +262,7 @@ ImGuiIO::ImGuiIO()
 	LogFilename = "imgui_log.txt";
 	Font = NULL;
 	FontAllowScaling = false;
+	PixelCenterOffset = 0.5f;
 	MousePos = ImVec2(-1,-1);
 	MousePosPrev = ImVec2(-1,-1);
 	MouseDoubleClickTime = 0.30f;
@@ -5000,6 +5004,8 @@ void ImBitmapFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& c
 	float line_width = 0.0f;
 	const ImVec4 clip_rect = clip_rect_ref;
 
+	const float uv_offset = GImGui.IO.PixelCenterOffset;
+
 	float x = pos.x;
 	float y = pos.y;
 	for (const char* s = text_begin; s < text_end; s++)
@@ -5036,10 +5042,10 @@ void ImBitmapFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& c
 					continue;
 				}
 
-				const float s1 = (0.0f + glyph->X) * tex_scale_x;
+				const float s1 = (uv_offset + glyph->X) * tex_scale_x;
-				const float t1 = (0.0f + glyph->Y) * tex_scale_y;
+				const float t1 = (uv_offset + glyph->Y) * tex_scale_y;
-				const float s2 = (0.0f + glyph->X + glyph->Width) * tex_scale_x;
+				const float s2 = (uv_offset + glyph->X + glyph->Width) * tex_scale_x;
-				const float t2 = (0.0f + glyph->Y + glyph->Height) * tex_scale_y;
+				const float t2 = (uv_offset + glyph->Y + glyph->Height) * tex_scale_y;
 
 				out_vertices[0].pos = ImVec2(x1, y1);
 				out_vertices[0].uv  = ImVec2(s1, t1);

imgui.h

@@ -373,6 +373,7 @@ struct ImGuiIO
 	ImFont		Font;						// <auto>					// Gets passed to text functions. Typedef ImFont to the type you want (ImBitmapFont* or your own font).
 	float		FontHeight;					// <auto>					// Default font height, must be the vertical distance between two lines of text, aka == CalcTextSize(" ").y
 	bool		FontAllowScaling;			// = false					// Set to allow scaling text with CTRL+Wheel.
+	float		PixelCenterOffset;			// = 0.5f					// Set to 0.0f for DirectX <= 9, 0.5f for Direct3D >= 10 and OpenGL.
 
 	// Settings - Functions (fill once)
 	void		(*RenderDrawListsFn)(ImDrawList** const draw_lists, int count);	// Required
@@ -380,7 +381,7 @@ struct ImGuiIO
 	void		(*SetClipboardTextFn)(const char* text, const char* text_end);	// Required for clipboard support (nb- the string is *NOT* zero-terminated at 'text_end')
 
 	// Input - Fill before calling NewFrame()
-	ImVec2		MousePos;					// Mouse position (set to -1,-1 if no mouse / on another screen, etc.)
+	ImVec2		MousePos;					// Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
 	bool		MouseDown[2];				// Mouse buttons
 	int			MouseWheel;					// Mouse wheel: -1,0,+1
 	bool		KeyCtrl;					// Keyboard modifier pressed: Control