Merge branch 'tseeker/20171127-feature-horiz-wheel' of https://github.com/tseeker/imgui into tseeker-tseeker/20171127-feature-horiz-wheel

# Conflicts:
#	examples/sdl_opengl2_example/imgui_impl_sdl_gl2.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp

examples/opengl2_example/imgui_impl_glfw_gl2.cpp

@@ -31,6 +31,7 @@
 static GLFWwindow*  g_Window = NULL;
 static double       g_Time = 0.0f;
 static bool         g_MouseJustPressed[3] = { false, false, false };
+static float        g_MouseHorizWheel = 0.0f;
 static float        g_MouseWheel = 0.0f;
 static GLuint       g_FontTexture = 0;
 
@@ -134,9 +135,10 @@ void ImGui_ImplGlfwGL2_MouseButtonCallback(GLFWwindow*, int button, int action,
         g_MouseJustPressed[button] = true;
 }
 
-void ImGui_ImplGlfwGL2_ScrollCallback(GLFWwindow*, double /*xoffset*/, double yoffset)
+void ImGui_ImplGlfwGL2_ScrollCallback(GLFWwindow*, double xoffset, double yoffset)
 {
-    g_MouseWheel += (float)yoffset; // Use fractional mouse wheel.
+    g_MouseHorizWheel += (float)xoffset; // Use fractional mouse wheel.
+    g_MouseWheel += (float)yoffset;
 }
 
 void ImGui_ImplGlfwGL2_KeyCallback(GLFWwindow*, int key, int, int action, int mods)
@@ -295,8 +297,9 @@ void ImGui_ImplGlfwGL2_NewFrame()
         g_MouseJustPressed[i] = false;
     }
 
+    io.MouseHorizWheel = g_MouseHorizWheel;
     io.MouseWheel = g_MouseWheel;
-    g_MouseWheel = 0.0f;
+    g_MouseHorizWheel = g_MouseWheel = 0.0f;
 
     // Hide OS mouse cursor if ImGui is drawing it
     glfwSetInputMode(g_Window, GLFW_CURSOR, io.MouseDrawCursor ? GLFW_CURSOR_HIDDEN : GLFW_CURSOR_NORMAL);

examples/opengl3_example/imgui_impl_glfw_gl3.cpp

@@ -25,6 +25,7 @@
 static GLFWwindow*  g_Window = NULL;
 static double       g_Time = 0.0f;
 static bool         g_MouseJustPressed[3] = { false, false, false };
+static float        g_MouseHorizWheel = 0.0f;
 static float        g_MouseWheel = 0.0f;
 static GLuint       g_FontTexture = 0;
 static int          g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
@@ -155,9 +156,10 @@ void ImGui_ImplGlfwGL3_MouseButtonCallback(GLFWwindow*, int button, int action,
         g_MouseJustPressed[button] = true;
 }
 
-void ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow*, double /*xoffset*/, double yoffset)
+void ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow*, double xoffset, double yoffset)
 {
-    g_MouseWheel += (float)yoffset; // Use fractional mouse wheel.
+    g_MouseHorizWheel += (float)xoffset; // Use fractional mouse wheel.
+    g_MouseWheel += (float)yoffset;
 }
 
 void ImGui_ImplGlfwGL3_KeyCallback(GLFWwindow*, int key, int, int action, int mods)
@@ -407,8 +409,9 @@ void ImGui_ImplGlfwGL3_NewFrame()
         g_MouseJustPressed[i] = false;
     }
 
+    io.MouseHorizWheel = g_MouseHorizWheel;
     io.MouseWheel = g_MouseWheel;
-    g_MouseWheel = 0.0f;
+    g_MouseHorizWheel = g_MouseWheel = 0.0f;
 
     // Hide OS mouse cursor if ImGui is drawing it
     glfwSetInputMode(g_Window, GLFW_CURSOR, io.MouseDrawCursor ? GLFW_CURSOR_HIDDEN : GLFW_CURSOR_NORMAL);

examples/sdl_opengl2_example/imgui_impl_sdl_gl2.cpp

@@ -24,6 +24,7 @@
 // Data
 static double       g_Time = 0.0f;
 static bool         g_MousePressed[3] = { false, false, false };
+static float        g_MouseHorizWheel = 0.0f;
 static float        g_MouseWheel = 0.0f;
 static GLuint       g_FontTexture = 0;
 
@@ -132,6 +133,10 @@ bool ImGui_ImplSdlGL2_ProcessEvent(SDL_Event* event)
     {
     case SDL_MOUSEWHEEL:
         {
+            if (event->wheel.x > 0)
+                g_MouseHorizWheel = 1;
+            if (event->wheel.x < 0)
+                g_MouseHorizWheel = -1;
             if (event->wheel.y > 0)
                 g_MouseWheel = 1;
             if (event->wheel.y < 0)
@@ -275,11 +280,12 @@ void ImGui_ImplSdlGL2_NewFrame(SDL_Window *window)
     Uint32 mouse_buttons = SDL_GetMouseState(&mx, &my);
     io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
     io.MouseWheel = g_MouseWheel;
+    io.MouseHorizWheel = g_MouseHorizWheel;
     io.MouseDown[0] = g_MousePressed[0] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_LEFT)) != 0;  // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
     io.MouseDown[1] = g_MousePressed[1] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_RIGHT)) != 0;
     io.MouseDown[2] = g_MousePressed[2] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_MIDDLE)) != 0;
     g_MousePressed[0] = g_MousePressed[1] = g_MousePressed[2] = false;
-    g_MouseWheel = 0.0f;
+    g_MouseWheel = g_MouseHorizWheel = 0.0f;
 
     // We need to use SDL_CaptureMouse() to easily retrieve mouse coordinates outside of the client area. This is only supported from SDL 2.0.4 (released Jan 2016)
 #if (SDL_MAJOR_VERSION >= 2) && (SDL_MINOR_VERSION >= 0) && (SDL_PATCHLEVEL >= 4)   

examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp

@@ -19,6 +19,7 @@
 // Data
 static double       g_Time = 0.0f;
 static bool         g_MousePressed[3] = { false, false, false };
+static float        g_MouseHorizWheel = 0.0f;
 static float        g_MouseWheel = 0.0f;
 static GLuint       g_FontTexture = 0;
 static int          g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
@@ -154,6 +155,10 @@ bool ImGui_ImplSdlGL3_ProcessEvent(SDL_Event* event)
     {
     case SDL_MOUSEWHEEL:
         {
+            if (event->wheel.x > 0)
+                g_MouseHorizWheel = 1;
+            if (event->wheel.x < 0)
+                g_MouseHorizWheel = -1;
             if (event->wheel.y > 0)
                 g_MouseWheel = 1;
             if (event->wheel.y < 0)
@@ -386,11 +391,12 @@ void ImGui_ImplSdlGL3_NewFrame(SDL_Window* window)
     Uint32 mouse_buttons = SDL_GetMouseState(&mx, &my);
     io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
     io.MouseWheel = g_MouseWheel;
+    io.MouseHorizWheel = g_MouseHorizWheel;
     io.MouseDown[0] = g_MousePressed[0] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_LEFT)) != 0;  // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
     io.MouseDown[1] = g_MousePressed[1] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_RIGHT)) != 0;
     io.MouseDown[2] = g_MousePressed[2] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_MIDDLE)) != 0;
     g_MousePressed[0] = g_MousePressed[1] = g_MousePressed[2] = false;
-    g_MouseWheel = 0.0f;
+    g_MouseHorizWheel = g_MouseWheel = 0.0f;
 
     // We need to use SDL_CaptureMouse() to easily retrieve mouse coordinates outside of the client area. This is only supported from SDL 2.0.4 (released Jan 2016)
 #if (SDL_MAJOR_VERSION >= 2) && (SDL_MINOR_VERSION >= 0) && (SDL_PATCHLEVEL >= 4)   

imgui.cpp

@@ -639,6 +639,7 @@ static bool             IsKeyPressedMap(ImGuiKey key, bool repeat = true);
 static ImFont*          GetDefaultFont();
 static void             SetCurrentFont(ImFont* font);
 static void             SetCurrentWindow(ImGuiWindow* window);
+static void             SetWindowScrollX(ImGuiWindow* window, float new_scroll_x);
 static void             SetWindowScrollY(ImGuiWindow* window, float new_scroll_y);
 static void             SetWindowPos(ImGuiWindow* window, const ImVec2& pos, ImGuiCond cond);
 static void             SetWindowSize(ImGuiWindow* window, const ImVec2& size, ImGuiCond cond);
@@ -2516,6 +2517,16 @@ void ImGui::NewFrame()
         }
     }
 
+    // Horizontal wheel scrolling; for consistency, only allowed if Ctrl is not pressed.
+    if (g.HoveredWindow && g.IO.MouseHorizWheel != 0.0f && !g.HoveredWindow->Collapsed)
+    {
+        ImGuiWindow* window = g.HoveredWindow;
+        if (!g.IO.KeyCtrl && !(window->Flags & ImGuiWindowFlags_NoScrollWithMouse))
+        {
+            SetWindowScrollX(window, window->Scroll.x - g.IO.MouseHorizWheel * 10.f);
+        }
+    }
+
     // Pressing TAB activate widget focus
     if (g.ActiveId == 0 && g.NavWindow != NULL && g.NavWindow->Active && IsKeyPressedMap(ImGuiKey_Tab, false))
         g.NavWindow->FocusIdxTabRequestNext = 0;
@@ -5609,6 +5620,13 @@ ImVec2 ImGui::GetWindowPos()
     return window->Pos;
 }
 
+static void SetWindowScrollX(ImGuiWindow* window, float new_scroll_x)
+{
+    window->DC.CursorMaxPos.x += window->Scroll.x; // SizeContents is generally computed based on CursorMaxPos which is affected by scroll position, so we need to apply our change to it.
+    window->Scroll.x = new_scroll_x;
+    window->DC.CursorMaxPos.x -= window->Scroll.x;
+}
+
 static void SetWindowScrollY(ImGuiWindow* window, float new_scroll_y)
 {
     window->DC.CursorMaxPos.y += window->Scroll.y; // SizeContents is generally computed based on CursorMaxPos which is affected by scroll position, so we need to apply our change to it.

imgui.h

@@ -931,6 +931,7 @@ struct ImGuiIO
     ImVec2      MousePos;                   // Mouse position, in pixels. Set to ImVec2(-FLT_MAX,-FLT_MAX) if mouse is unavailable (on another screen, etc.)
     bool        MouseDown[5];               // Mouse buttons: left, right, middle + extras. ImGui itself mostly only uses left button (BeginPopupContext** are using right button). Others buttons allows us to track if the mouse is being used by your application + available to user as a convenience via IsMouse** API.
     float       MouseWheel;                 // Mouse wheel: 1 unit scrolls about 5 lines text.
+    float       MouseHorizWheel;            // Horizontal mouse wheel
     bool        MouseDrawCursor;            // Request ImGui to draw a mouse cursor for you (if you are on a platform without a mouse cursor).
     bool        KeyCtrl;                    // Keyboard modifier pressed: Control
     bool        KeyShift;                   // Keyboard modifier pressed: Shift