diff --git a/docs/TODO.txt b/docs/TODO.txt index 4c2a2037..8b60c057 100644 --- a/docs/TODO.txt +++ b/docs/TODO.txt @@ -31,6 +31,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i - window: freeze window flag: if not focused/hovered, return false, render with previous ImDrawList. and/or reduce refresh rate. - window: investigate better auto-positioning for new windows. - window/child: the first draw command of a child window could be moved into the current draw command of the parent window (unless child+tooltip?). + - scrolling: while holding down a scrollbar, try to keep the same contents visible (at least while not moving mouse) - scrolling: allow immediately effective change of scroll after Begin() if we haven't appended items yet. - scrolling/clipping: separator on the initial position of a window is not visible (cursorpos.y <= clippos.y). (2017-08-20: can't repro) - scrolling/style: shadows on scrollable areas to denote that there is more contents diff --git a/imgui_demo.cpp b/imgui_demo.cpp index a5f8f86c..856531b9 100644 --- a/imgui_demo.cpp +++ b/imgui_demo.cpp @@ -3375,10 +3375,15 @@ struct ExampleAppLog { ImGuiTextBuffer Buf; ImGuiTextFilter Filter; - ImVector LineOffsets; // Index to lines offset + ImVector LineOffsets; // Index to lines offset. We maintain this with AddLog() calls, allowing us to have a random access on lines bool ScrollToBottom; - void Clear() { Buf.clear(); LineOffsets.clear(); } + void Clear() + { + Buf.clear(); + LineOffsets.clear(); + LineOffsets.push_back(0); + } void AddLog(const char* fmt, ...) IM_FMTARGS(2) { @@ -3389,13 +3394,12 @@ struct ExampleAppLog va_end(args); for (int new_size = Buf.size(); old_size < new_size; old_size++) if (Buf[old_size] == '\n') - LineOffsets.push_back(old_size); + LineOffsets.push_back(old_size + 1); ScrollToBottom = true; } void Draw(const char* title, bool* p_open = NULL) { - ImGui::SetNextWindowSize(ImVec2(500,400), ImGuiCond_FirstUseEver); if (!ImGui::Begin(title, p_open)) { ImGui::End(); @@ -3408,24 +3412,47 @@ struct ExampleAppLog Filter.Draw("Filter", -100.0f); ImGui::Separator(); ImGui::BeginChild("scrolling", ImVec2(0,0), false, ImGuiWindowFlags_HorizontalScrollbar); - if (copy) ImGui::LogToClipboard(); + if (copy) + ImGui::LogToClipboard(); + ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(0, 0)); + const char* buf = Buf.begin(); + const char* buf_end = Buf.end(); if (Filter.IsActive()) { - const char* buf_begin = Buf.begin(); - const char* line = buf_begin; - for (int line_no = 0; line != NULL; line_no++) + for (int line_no = 0; line_no < LineOffsets.Size; line_no++) { - const char* line_end = (line_no < LineOffsets.Size) ? buf_begin + LineOffsets[line_no] : NULL; - if (Filter.PassFilter(line, line_end)) - ImGui::TextUnformatted(line, line_end); - line = line_end && line_end[1] ? line_end + 1 : NULL; + const char* line_start = buf + LineOffsets[line_no]; + const char* line_end = (line_no + 1 < LineOffsets.Size) ? (buf + LineOffsets[line_no + 1] - 1) : buf_end; + if (Filter.PassFilter(line_start, line_end)) + ImGui::TextUnformatted(line_start, line_end); } } else { - ImGui::TextUnformatted(Buf.begin()); + // The simplest and easy way to display the entire buffer: + // ImGui::TextUnformatted(buf_begin, buf_end); + // And it'll just work. TextUnformatted() has specialization for large blob of text and will fast-forward to skip non-visible lines. + // Here we instead demonstrate using the clipper to only process lines that are within the visible area. + // If you have tens of thousands of items and their processing cost is non-negligible, coarse clipping them on your side is recommended. + // Using ImGuiListClipper requires A) random access into your data, and B) items all being the same height, + // both of which we can handle since we an array pointing to the beginning of each line of text. + // When using the filter (in the block of code above) we don't have random access into the data to display anymore, which is why we don't use the clipper. + // Storing or skimming through the search result would make it possible (and would be recommended if you want to search through tens of thousands of entries) + ImGuiListClipper clipper; + clipper.Begin(LineOffsets.Size); + while (clipper.Step()) + { + for (int line_no = clipper.DisplayStart; line_no < clipper.DisplayEnd; line_no++) + { + const char* line_start = buf + LineOffsets[line_no]; + const char* line_end = (line_no + 1 < LineOffsets.Size) ? (buf + LineOffsets[line_no + 1] - 1) : buf_end; + ImGui::TextUnformatted(line_start, line_end); + } + } + clipper.End(); } + ImGui::PopStyleVar(); if (ScrollToBottom) ImGui::SetScrollHereY(1.0f); @@ -3440,15 +3467,23 @@ static void ShowExampleAppLog(bool* p_open) { static ExampleAppLog log; - // Demo: add random items (unless Ctrl is held) - static double last_time = -1.0; - double time = ImGui::GetTime(); - if (time - last_time >= 0.20f && !ImGui::GetIO().KeyCtrl) + // For the demo: add a debug button before the normal log window contents + // We take advantage of the fact that multiple calls to Begin()/End() are appending to the same window. + ImGui::SetNextWindowSize(ImVec2(500, 400), ImGuiCond_FirstUseEver); + ImGui::Begin("Example: Log", p_open); + if (ImGui::SmallButton("Add 5 entries")) { - const char* random_words[] = { "system", "info", "warning", "error", "fatal", "notice", "log" }; - log.AddLog("[%s] Hello, time is %.1f, frame count is %d\n", random_words[rand() % IM_ARRAYSIZE(random_words)], time, ImGui::GetFrameCount()); - last_time = time; + static int counter = 0; + for (int n = 0; n < 5; n++) + { + const char* categories[3] = { "info", "warn", "error" }; + const char* words[] = { "Bumfuzzled", "Cattywampus", "Snickersnee", "Abibliophobia", "Absquatulate", "Nincompoop", "Pauciloquent" }; + log.AddLog("[%05d] [%s] Hello, current time is %.1f, here's a word: '%s'\n", + ImGui::GetFrameCount(), categories[counter % IM_ARRAYSIZE(categories)], ImGui::GetTime(), words[counter % IM_ARRAYSIZE(words)]); + counter++; + } } + ImGui::End(); log.Draw("Example: Log", p_open); }