Fix progress bar display when terminal width is too small

When the terminal width is too small, we run into problems as mentioned
in #132. This PR fixes the
problem by keeping track of number of wrapped lines printed by progress
bar and erasing those extra wrapped lines before printing progress for
next iteration.

For multi_progress bar and dynamic_progress bar, we need to move cursor
to start before each iteration by summing up number of wrapped lines for
each bar. Since each bar's `print_progress` expects cursor to be on last
printed line, we move cursor down by number of wrapped lines before
printing progress for each bar.

I have not yet handled case when `dynamic_progress` option
`hide_bar_when_complete` is set.

Fixes Issue #132

Author: vawale

include/indicators/block_progress_bar.hpp

@@ -4,6 +4,7 @@
 
 #include <indicators/color.hpp>
 #include <indicators/details/stream_helper.hpp>
+#include <indicators/cursor_control.hpp>
 
 #include <algorithm>
 #include <atomic>
@@ -12,8 +13,8 @@
 #include <indicators/terminal_size.hpp>
 #include <iomanip>
 #include <iostream>
-#include <sstream>
 #include <mutex>
+#include <sstream>
 #include <string>
 #include <thread>
 #include <tuple>
@@ -33,7 +34,7 @@ class BlockProgressBar {
             typename std::enable_if<details::are_settings_from_tuple<
                                         Settings, typename std::decay<Args>::type...>::value,
                                     void *>::type = nullptr>
-  explicit BlockProgressBar(Args &&... args)
+  explicit BlockProgressBar(Args &&...args)
       : settings_(details::get<details::ProgressBarOption::foreground_color>(
                       option::ForegroundColor{Color::unspecified}, std::forward<Args>(args)...),
                   details::get<details::ProgressBarOption::bar_width>(option::BarWidth{100},
@@ -123,7 +124,7 @@ class BlockProgressBar {
   size_t current() {
     std::lock_guard<std::mutex> lock{mutex_};
     return (std::min)(static_cast<size_t>(progress_),
-                    size_t(get_value<details::ProgressBarOption::max_progress>()));
+                      size_t(get_value<details::ProgressBarOption::max_progress>()));
   }
 
   bool is_completed() const { return get_value<details::ProgressBarOption::completed>(); }
@@ -133,22 +134,28 @@ class BlockProgressBar {
     print_progress();
   }
 
+  size_t extra_wrapped_lines() {
+    std::lock_guard<std::mutex> lock{mutex_};
+    return extra_wrapped_lines_;
+  }
+
 private:
   template <details::ProgressBarOption id>
   auto get_value() -> decltype((details::get_value<id>(std::declval<Settings &>()).value)) {
     return details::get_value<id>(settings_).value;
   }
 
   template <details::ProgressBarOption id>
-  auto get_value() const
-      -> decltype((details::get_value<id>(std::declval<const Settings &>()).value)) {
+  auto
+  get_value() const -> decltype((details::get_value<id>(std::declval<const Settings &>()).value)) {
     return details::get_value<id>(settings_).value;
   }
 
   Settings settings_;
   float progress_{0.0};
   std::chrono::time_point<std::chrono::high_resolution_clock> start_time_point_;
   std::mutex mutex_;
+  size_t extra_wrapped_lines_{0};
 
   template <typename Indicator, size_t count> friend class MultiProgress;
   template <typename Indicator> friend class DynamicProgress;
@@ -201,10 +208,9 @@ class BlockProgressBar {
 
       if (saved_start_time) {
         auto eta = std::chrono::nanoseconds(
-            progress_ > 0
-                ? static_cast<long long>(std::ceil(float(elapsed.count()) *
-                                                   max_progress / progress_))
-                : 0);
+            progress_ > 0 ? static_cast<long long>(
+                                std::ceil(float(elapsed.count()) * max_progress / progress_))
+                          : 0);
         auto remaining = eta > elapsed ? (eta - elapsed) : (elapsed - eta);
         details::write_duration(os, remaining);
       } else {
@@ -244,6 +250,10 @@ class BlockProgressBar {
     for (auto &style : get_value<details::ProgressBarOption::font_styles>())
       details::set_font_style(os, style);
 
+    // Need to erase previously written text across multiple lines to solve
+    // issue https://github.com/p-ranav/indicators/issues/132
+    erase_lines(extra_wrapped_lines_);
+
     const auto prefix_pair = get_prefix_text();
     const auto prefix_text = prefix_pair.first;
     const auto prefix_length = prefix_pair.second;
@@ -267,17 +277,19 @@ class BlockProgressBar {
     const auto bar_width = get_value<details::ProgressBarOption::bar_width>();
     const auto end_length = get_value<details::ProgressBarOption::end>().size();
     const auto terminal_width = terminal_size().second;
-    // prefix + bar_width + postfix should be <= terminal_width
-    const int remaining = terminal_width - (prefix_length + start_length + bar_width + end_length + postfix_length);
+    const auto number_of_characters =
+        prefix_length + start_length + bar_width + end_length + postfix_length;
+    // If prefix + bar_width + postfix > terminal_width, lines will be wrapped
+    const int remaining = terminal_width - number_of_characters;
     if (prefix_length == -1 || postfix_length == -1) {
       os << "\r";
     } else if (remaining > 0) {
       os << std::string(remaining, ' ') << "\r";
-    } else if (remaining < 0) {
-      // Do nothing. Maybe in the future truncate postfix with ...
     }
     os.flush();
 
+    extra_wrapped_lines_ = details::extra_wrapped_lines(number_of_characters);
+
     if (progress_ > max_progress) {
       get_value<details::ProgressBarOption::completed>() = true;
     }

include/indicators/cursor_control.hpp

@@ -2,6 +2,8 @@
 #ifndef INDICATORS_CURSOR_CONTROL
 #define INDICATORS_CURSOR_CONTROL
 
+#include <indicators/cursor_movement.hpp>
+
 #if defined(_MSC_VER)
 #if !defined(NOMINMAX)
 #define NOMINMAX
@@ -61,6 +63,13 @@ static inline void erase_line() {
 
 #endif
 
+static inline void erase_lines(size_t lines) {
+  for (size_t i = 0; i < lines; ++i) {
+    move_up(1);
+    erase_line();
+  }
+}
+
 } // namespace indicators
 
 #endif

include/indicators/details/stream_helper.hpp

@@ -5,6 +5,7 @@
 #include <indicators/display_width.hpp>
 #include <indicators/setting.hpp>
 #include <indicators/termcolor.hpp>
+#include <indicators/terminal_size.hpp>
 
 #include <algorithm>
 #include <chrono>
@@ -217,6 +218,17 @@ class IndeterminateProgressScaleWriter {
   std::string lead;
 };
 
+inline size_t extra_wrapped_lines(size_t number_of_characters)
+{
+  const auto number_of_columns = indicators::terminal_width();
+  const auto extra_lines = number_of_characters / number_of_columns;
+  // cursor does not wrap when writing to the last column
+  if ((extra_lines > 0) && (number_of_characters % number_of_columns) == 0) {
+    return extra_lines-1;
+  }
+  return extra_lines;
+}
+
 } // namespace details
 } // namespace indicators
 

include/indicators/dynamic_progress.hpp

@@ -2,13 +2,15 @@
 #ifndef INDICATORS_DYNAMIC_PROGRESS
 #define INDICATORS_DYNAMIC_PROGRESS
 
-#include <atomic>
-#include <functional>
 #include <indicators/color.hpp>
 #include <indicators/setting.hpp>
 #include <indicators/cursor_control.hpp>
 #include <indicators/cursor_movement.hpp>
 #include <indicators/details/stream_helper.hpp>
+
+#include <atomic>
+#include <functional>
+#include <numeric>
 #include <iostream>
 #include <mutex>
 #include <vector>
@@ -103,9 +105,19 @@ template <typename Indicator> class DynamicProgress {
         started_ = true;
     } else {
       // Don't hide any bars
-      if (started_)
-        move_up(static_cast<int>(total_count_));
+      if (started_) {
+        // move all the way up to start of first progress bar
+        const auto wrapped_lines = std::accumulate(begin(bars_), end(bars_), 0, [](size_t acc, auto &bar) {
+          return acc + bar.get().extra_wrapped_lines();
+        });
+        move_up(total_count_ + wrapped_lines);
+      }
       for (auto &bar : bars_) {
+        auto wrapped_line = bar.get().extra_wrapped_lines();
+        if (wrapped_line > 0) {
+          // for each bar before calling `print_progress`, cursor needs to be on last line that bar printed
+          move_down(wrapped_line);
+        }
         bar.get().print_progress(true);
         std::cout << "\n";
       }

include/indicators/indeterminate_progress_bar.hpp

@@ -3,6 +3,7 @@
 #define INDICATORS_INDETERMINATE_PROGRESS_BAR
 
 #include <indicators/details/stream_helper.hpp>
+#include <indicators/cursor_control.hpp>
 
 #include <algorithm>
 #include <atomic>
@@ -138,6 +139,11 @@ class IndeterminateProgressBar {
     print_progress();
   }
 
+  size_t extra_wrapped_lines() {
+    std::lock_guard<std::mutex> lock{mutex_};
+    return extra_wrapped_lines_;
+  }
+
 private:
   template <details::ProgressBarOption id>
   auto get_value() -> decltype((details::get_value<id>(std::declval<Settings &>()).value)) {
@@ -155,6 +161,7 @@ class IndeterminateProgressBar {
   Settings settings_;
   std::chrono::nanoseconds elapsed_;
   std::mutex mutex_;
+  size_t extra_wrapped_lines_{0};
 
   template <typename Indicator, size_t count> friend class MultiProgress;
   template <typename Indicator> friend class DynamicProgress;
@@ -191,6 +198,10 @@ class IndeterminateProgressBar {
 
     for (auto &style : get_value<details::ProgressBarOption::font_styles>())
       details::set_font_style(os, style);
+    
+    // Need to erase previously written text across multiple lines to solve
+    // issue https://github.com/p-ranav/indicators/issues/132
+    erase_lines(extra_wrapped_lines_);
 
     const auto prefix_pair = get_prefix_text();
     const auto prefix_text = prefix_pair.first;
@@ -217,17 +228,18 @@ class IndeterminateProgressBar {
     const auto bar_width = get_value<details::ProgressBarOption::bar_width>();
     const auto end_length = get_value<details::ProgressBarOption::end>().size();
     const auto terminal_width = terminal_size().second;
-    // prefix + bar_width + postfix should be <= terminal_width
-    const int remaining = terminal_width - (prefix_length + start_length + bar_width + end_length + postfix_length);
+    const auto number_of_characters = prefix_length + start_length + bar_width + end_length + postfix_length;
+    // If prefix + bar_width + postfix > terminal_width, lines will be wrapped
+    const int remaining = terminal_width - number_of_characters;
     if (prefix_length == -1 || postfix_length == -1) {
       os << "\r";
     } else if (remaining > 0) {
       os << std::string(remaining, ' ') << "\r";
-    } else if (remaining < 0) {
-      // Do nothing. Maybe in the future truncate postfix with ...
     }
     os.flush();
 
+    extra_wrapped_lines_ = details::extra_wrapped_lines(number_of_characters);
+
     if (get_value<details::ProgressBarOption::completed>() &&
         !from_multi_progress) // Don't std::endl if calling from MultiProgress
       os << termcolor::reset << std::endl;

include/indicators/multi_progress.hpp

@@ -6,6 +6,7 @@
 #include <iostream>
 #include <mutex>
 #include <vector>
+#include <numeric>
 
 #include <indicators/color.hpp>
 #include <indicators/cursor_movement.hpp>
@@ -65,9 +66,21 @@ template <typename Indicator, size_t count> class MultiProgress {
 public:
   void print_progress() {
     std::lock_guard<std::mutex> lock{mutex_};
-    if (started_)
-      move_up(count);
+    
+    if (started_) {
+      // move all the way up to start of first progress bar
+      const auto wrapped_lines = std::accumulate(begin(bars_), end(bars_), 0, [](size_t acc, auto &bar) {
+        return acc + bar.get().extra_wrapped_lines();
+      });
+      move_up(count + wrapped_lines);
+    }
+
     for (auto &bar : bars_) {
+      auto wrapped_line = bar.get().extra_wrapped_lines();
+      if (wrapped_line > 0) {
+        // for each bar before calling `print_progress`, cursor needs to be on last line that bar printed
+        move_down(wrapped_line);
+      }
       bar.get().print_progress(true);
       std::cout << "\n";
     }

include/indicators/progress_bar.hpp

@@ -3,6 +3,7 @@
 #define INDICATORS_PROGRESS_BAR
 
 #include <indicators/details/stream_helper.hpp>
+#include <indicators/cursor_control.hpp>
 
 #include <algorithm>
 #include <atomic>
@@ -180,6 +181,11 @@ class ProgressBar {
     print_progress();
   }
 
+  size_t extra_wrapped_lines() {
+    std::lock_guard<std::mutex> lock{mutex_};
+    return extra_wrapped_lines_;
+  }
+
 private:
   template <details::ProgressBarOption id>
   auto get_value()
@@ -198,6 +204,7 @@ class ProgressBar {
   std::chrono::nanoseconds elapsed_;
   std::chrono::time_point<std::chrono::high_resolution_clock> start_time_point_;
   std::mutex mutex_;
+  size_t extra_wrapped_lines_{0};
 
   template <typename Indicator, size_t count> friend class MultiProgress;
   template <typename Indicator> friend class DynamicProgress;
@@ -310,6 +317,10 @@ class ProgressBar {
     for (auto &style : get_value<details::ProgressBarOption::font_styles>())
       details::set_font_style(os, style);
 
+    // Need to erase previously written text across multiple lines to solve
+    // issue https://github.com/p-ranav/indicators/issues/132
+    erase_lines(extra_wrapped_lines_);
+    
     const auto prefix_pair = get_prefix_text();
     const auto prefix_text = prefix_pair.first;
     const auto prefix_length = prefix_pair.second;
@@ -336,17 +347,18 @@ class ProgressBar {
     const auto bar_width = get_value<details::ProgressBarOption::bar_width>();
     const auto end_length = get_value<details::ProgressBarOption::end>().size();
     const auto terminal_width = terminal_size().second;
-    // prefix + bar_width + postfix should be <= terminal_width
-    const int remaining = terminal_width - (prefix_length + start_length + bar_width + end_length + postfix_length);
+    const auto number_of_characters = prefix_length + start_length + bar_width + end_length + postfix_length;
+    // If prefix + bar_width + postfix > terminal_width, lines will be wrapped
+    const int remaining = terminal_width - number_of_characters;
     if (prefix_length == -1 || postfix_length == -1) {
       os << "\r";
     } else if (remaining > 0) {
       os << std::string(remaining, ' ') << "\r";
-    } else if (remaining < 0) {
-      // Do nothing. Maybe in the future truncate postfix with ...
     }
     os.flush();
 
+    extra_wrapped_lines_ = details::extra_wrapped_lines(number_of_characters);
+
     if ((type == ProgressType::incremental && progress_ >= max_progress) ||
         (type == ProgressType::decremental && progress_ <= min_progress)) {
       get_value<details::ProgressBarOption::completed>() = true;