diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt index ea67baa6..70acf40c 100644 --- a/docs/CHANGELOG.txt +++ b/docs/CHANGELOG.txt @@ -68,6 +68,8 @@ Other Changes: by modifying the 'style.CircleSegmentMaxError' value. [@ShironekoBen] - ImDrawList: Fixed minor bug introduced in 1.75 where AddCircle() with 12 segments would generate an extra vertex. (This bug was mistakenly marked as fixed in earlier 1.77 release). [@ShironekoBen] +- Demo: Improve "Custom Rendering"->"Canvas" demo with a grid, scrolling and context menu. + Also showcase using InvisibleButton() will multiple mouse buttons flags. - Demo: Tweak "Child Windows" section. - Style Editor: Added preview of circle auto-tessellation when editing the corresponding value. - Backends: OpenGL3: Added support for glad2 loader. (#3330) [@moritz-h] diff --git a/imgui_demo.cpp b/imgui_demo.cpp index 2acee763..0ce046c5 100644 --- a/imgui_demo.cpp +++ b/imgui_demo.cpp @@ -4859,13 +4859,13 @@ static void ShowExampleAppCustomRendering(bool* p_open) // overloaded operators, etc. Define IM_VEC2_CLASS_EXTRA in imconfig.h to create implicit conversions between your // types and ImVec2/ImVec4. Dear ImGui defines overloaded operators but they are internal to imgui.cpp and not // exposed outside (to avoid messing with your types) In this example we are not using the maths operators! - ImDrawList* draw_list = ImGui::GetWindowDrawList(); if (ImGui::BeginTabBar("##TabBar")) { if (ImGui::BeginTabItem("Primitives")) { ImGui::PushItemWidth(-ImGui::GetFontSize() * 10); + ImDrawList* draw_list = ImGui::GetWindowDrawList(); // Draw gradients // (note that those are currently exacerbating our sRGB/Linear issues) @@ -4949,56 +4949,95 @@ static void ShowExampleAppCustomRendering(bool* p_open) if (ImGui::BeginTabItem("Canvas")) { - static ImVector points; + struct ItemLine { ImVec2 p0, p1; ItemLine(const ImVec2& _p0, const ImVec2& _p1) { p0 = _p0; p1 = _p1; } }; + static ImVector lines; + static ImVec2 scrolling(0.0f, 0.0f); + static bool show_grid = true; static bool adding_line = false; - if (ImGui::Button("Clear")) points.clear(); - if (points.Size >= 2) { ImGui::SameLine(); if (ImGui::Button("Undo")) { points.pop_back(); points.pop_back(); } } - ImGui::Text("Left-click and drag to add lines,\nRight-click to undo"); - // Here we are using InvisibleButton() as a convenience to 1) advance the cursor and 2) allows us to use - // IsItemHovered(). But you can also draw directly and poll mouse/keyboard by yourself. - // You can manipulate the cursor using GetCursorPos() and SetCursorPos(). - // If you only use the ImDrawList API, you can notify the owner window of its extends with SetCursorPos(max). - ImVec2 canvas_p = ImGui::GetCursorScreenPos(); // ImDrawList API uses screen coordinates! + ImGui::Checkbox("Show grid", &show_grid); + ImGui::Text("Mouse Left: drag to add lines,\nMouse Right: drag to scroll, click for context menu."); + + // Typically you would use a BeginChild()/EndChild() pair to benefit from a clipping region + own scrolling. + // Here we demonstrate that this can be replaced by simple offsetting + custom drawing + PushClipRect/PopClipRect() calls. + // To use a child window instead we could use, e.g: + // ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0, 0)); // Disable padding + // ImGui::PushStyleColor(ImGuiCol_ChildBg, IM_COL32(50, 50, 50, 255)); // Set a background color + // ImGui::BeginChild("canvas", ImVec2(0.0f, 0.0f), true, ImGuiWindowFlags_NoMove); + // ImGui::PopStyleColor(); + // ImGui::PopStyleVar(); + // [...] + // ImGui::EndChild(); + + // Using InvisibleButton() as a convenience 1) it will advance the layout cursor and 2) allows us to use IsItemHovered()/IsItemActive() + ImVec2 canvas_p0 = ImGui::GetCursorScreenPos(); // ImDrawList API uses screen coordinates! ImVec2 canvas_sz = ImGui::GetContentRegionAvail(); // Resize canvas to what's available if (canvas_sz.x < 50.0f) canvas_sz.x = 50.0f; if (canvas_sz.y < 50.0f) canvas_sz.y = 50.0f; - draw_list->AddRectFilledMultiColor(canvas_p, ImVec2(canvas_p.x + canvas_sz.x, canvas_p.y + canvas_sz.y), IM_COL32(50, 50, 50, 255), IM_COL32(50, 50, 60, 255), IM_COL32(60, 60, 70, 255), IM_COL32(50, 50, 60, 255)); - draw_list->AddRect(canvas_p, ImVec2(canvas_p.x + canvas_sz.x, canvas_p.y + canvas_sz.y), IM_COL32(255, 255, 255, 255)); + ImVec2 canvas_p1 = ImVec2(canvas_p0.x + canvas_sz.x, canvas_p0.y + canvas_sz.y); - bool adding_preview = false; - ImGui::InvisibleButton("canvas", canvas_sz); - ImVec2 mouse_pos_global = ImGui::GetIO().MousePos; - ImVec2 mouse_pos_canvas = ImVec2(mouse_pos_global.x - canvas_p.x, mouse_pos_global.y - canvas_p.y); + // Draw border and background color + ImGuiIO& io = ImGui::GetIO(); + ImDrawList* draw_list = ImGui::GetWindowDrawList(); + draw_list->AddRectFilled(canvas_p0, canvas_p1, IM_COL32(50, 50, 50, 255)); + draw_list->AddRect(canvas_p0, canvas_p1, IM_COL32(255, 255, 255, 255)); + + // This will catch our interactions + ImGui::InvisibleButton("canvas", canvas_sz, ImGuiButtonFlags_MouseButtonLeft | ImGuiButtonFlags_MouseButtonRight); + const bool is_hovered = ImGui::IsItemHovered(); // Hovered + const bool is_active = ImGui::IsItemActive(); // Held + const ImVec2 origin(canvas_p0.x + scrolling.x, canvas_p0.y + scrolling.y); // Lock scrolled origin + const ImVec2 mouse_pos_in_canvas(io.MousePos.x - origin.x, io.MousePos.y - origin.y); + + // Add first and second point + if (is_hovered && !adding_line && ImGui::IsMouseClicked(ImGuiMouseButton_Left)) + { + lines.push_back(ItemLine(mouse_pos_in_canvas, mouse_pos_in_canvas)); + adding_line = true; + } if (adding_line) { - adding_preview = true; - points.push_back(mouse_pos_canvas); - if (!ImGui::IsMouseDown(0)) - adding_line = adding_preview = false; - } - if (ImGui::IsItemHovered()) - { - if (!adding_line && ImGui::IsMouseClicked(0)) - { - points.push_back(mouse_pos_canvas); - adding_line = true; - } - if (ImGui::IsMouseClicked(1) && !points.empty()) - { - adding_line = adding_preview = false; - points.pop_back(); - points.pop_back(); - } + lines.back().p1 = mouse_pos_in_canvas; + if (!ImGui::IsMouseDown(ImGuiMouseButton_Left)) + adding_line = false; } - // Draw all lines in the canvas (with a clipping rectangle so they don't stray out of it). - draw_list->PushClipRect(canvas_p, ImVec2(canvas_p.x + canvas_sz.x, canvas_p.y + canvas_sz.y), true); - for (int i = 0; i < points.Size - 1; i += 2) - draw_list->AddLine(ImVec2(canvas_p.x + points[i].x, canvas_p.y + points[i].y), ImVec2(canvas_p.x + points[i + 1].x, canvas_p.y + points[i + 1].y), IM_COL32(255, 255, 0, 255), 2.0f); + // Pan (using zero mouse threshold) + if (is_active && ImGui::IsMouseDragging(ImGuiMouseButton_Right, 0.0f)) + { + scrolling.x += io.MouseDelta.x; + scrolling.y += io.MouseDelta.y; + } + + // Context menu (under default mouse threshold) + // We intentionally use the same button to demonstrate using mouse drag threshold. Some may feel panning should rely on same threshold. + ImVec2 drag_delta = ImGui::GetMouseDragDelta(ImGuiMouseButton_Right); + if (drag_delta.x == 0.0f && drag_delta.y == 0.0f) + ImGui::OpenPopupContextItem("context"); + if (ImGui::BeginPopup("context")) + { + if (adding_line) + lines.pop_back(); + adding_line = false; + if (ImGui::MenuItem("Remove one", NULL, false, lines.Size > 0)) { lines.pop_back(); } + if (ImGui::MenuItem("Remove all", NULL, false, lines.Size > 0)) { lines.clear(); } + ImGui::EndPopup(); + } + + // Draw grid + all lines in the canvas + draw_list->PushClipRect(canvas_p0, canvas_p1, true); + if (show_grid) + { + const float GRID_STEP = 64.0f; + for (float x = fmodf(scrolling.x, GRID_STEP); x < canvas_sz.x; x += GRID_STEP) + draw_list->AddLine(ImVec2(canvas_p0.x + x, canvas_p0.y), ImVec2(canvas_p0.x + x, canvas_p1.y), IM_COL32(200, 200, 200, 40)); + for (float y = fmodf(scrolling.y, GRID_STEP); y < canvas_sz.y; y += GRID_STEP) + draw_list->AddLine(ImVec2(canvas_p0.x, canvas_p0.y + y), ImVec2(canvas_p1.x, canvas_p0.y + y), IM_COL32(200, 200, 200, 40)); + } + for (int n = 0; n < lines.Size; n++) + draw_list->AddLine(ImVec2(origin.x + lines[n].p0.x, origin.y + lines[n].p0.y), ImVec2(origin.x + lines[n].p1.x, origin.y + lines[n].p1.y), IM_COL32(255, 255, 0, 255), 2.0f); draw_list->PopClipRect(); - if (adding_preview) - points.pop_back(); + ImGui::EndTabItem(); }