Optimize log window

event_loop.cpp

@@ -19,10 +19,7 @@ static inline void check_for_logcat_items(LogcatThread& logcat_thread) {
 
     while ((logcat_thread_item = logcat_thread.atomic_ring_buffer.get())) {
         if (std::holds_alternative<std::string>(*logcat_thread_item)) {
-            if (!log_entries.empty()) {
+            log_raw(std::move(std::get<std::string>(*logcat_thread_item)), false);
-                log_entries += '\n';
-            }
-            log_entries += std::move(std::get<std::string>(*logcat_thread_item));
         } else if (std::holds_alternative<LogcatEntry>(*logcat_thread_item)) {
             LogcatEntry logcat_entry = std::move(std::get<LogcatEntry>(*logcat_thread_item));
             log("Received new logcat entry");
@@ -74,6 +71,7 @@ static inline void logs_window(ImFont* monospace_font, bool* autoscrolling, bool
 
     if (ImGui::Button("Clear")) {
         log_entries.clear();
+        log_entry_line_offsets = {0};
     }
     ImGui::SameLine();
     if (ImGui::Button("Copy")) {
@@ -82,9 +80,30 @@ static inline void logs_window(ImFont* monospace_font, bool* autoscrolling, bool
 
     ImGui::Separator();
     // copied from imgui/imgui_demo.cpp: [SECTION] Example App: Debug Console / ShowExampleAppConsole()
+    // and [SECTION] Example App: Long Text / ShowExampleAppLongText()
+    // and [SECTION] Example App: Debug Log / ShowExampleAppLog()
     if (ImGui::BeginChild("ScrollingRegion", ImVec2(0, 0), false, ImGuiWindowFlags_HorizontalScrollbar)) {
         ImGui::PushFont(monospace_font);
-        ImGui::TextUnformatted(log_entries.data(), &log_entries[log_entries.size()]);
+        ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(0, 0));
+
+        ImGuiListClipper clipper;
+        clipper.Begin(static_cast<int>(log_entry_line_offsets.size()));
+        while (clipper.Step()) {
+            for (int i_u = clipper.DisplayStart; i_u < clipper.DisplayEnd; i_u++) {
+                // what'd we do if we log the error about an error failing to show logs
+                assert(i_u >= 0);
+                size_t i = static_cast<size_t>(i_u);
+
+                const char* start_offset = &log_entries[log_entry_line_offsets[i]];
+                const char* end_offset = log_entry_line_offsets.size() > i + 1
+                    ? &log_entries[log_entry_line_offsets[i + 1] - 1]
+                    : &log_entries[log_entries.size()];
+                ImGui::TextUnformatted(start_offset, end_offset);
+            }
+        }
+        clipper.End();
+
+        ImGui::PopStyleVar();
         ImGui::PopFont();
         if (ImGui::GetScrollY() >= ImGui::GetScrollMaxY()) {
             *autoscrolling = true;

log.cpp

@@ -6,6 +6,7 @@
 #include "log.h"
 
 std::string log_entries;
+std::vector<size_t> log_entry_line_offsets = {0};
 
 std::string format_log(std::string entry, time_t time) {
     size_t newline_pos;
@@ -23,10 +24,13 @@ std::string format_log(std::string entry) {
     return format_log(std::move(entry), time(nullptr));
 }
 
-void log_raw(std::string line) {
+void log_raw(std::string line, bool print) {
+    if (print) {
         printf("%s\n", line.c_str());
+    }
     if (!log_entries.empty()) {
         log_entries += '\n';
+        log_entry_line_offsets.push_back(log_entries.size());
     }
     log_entries += std::move(line);
 }

log.h

@@ -5,9 +5,10 @@
 #include <exception>
 
 extern std::string log_entries;
+extern std::vector<size_t> log_entry_line_offsets;
 
 std::string format_log(std::string entry, time_t time);
 std::string format_log(std::string entry);
-void log_raw(std::string line);
+void log_raw(std::string line, bool print = true);
 void log(std::string entry, time_t time);
 void log(std::string entry);

myimconfig.h

@@ -3,6 +3,7 @@
 #include "log.h"
 
 #define IM_ASSERT_USER_ERROR(expr,msg) do { if (!(expr)) { log(msg); } } while (0);
+#define IMGUI_DISABLE_OBSOLETE_FUNCTIONS
 
 #ifndef NDEBUG
 #define IMGUI_DEBUG_PARANOID