Add option to not have any delays between anim/movie frames.

Not advertised in synopsis, this is mostly useful to create
canned terminal outputs, but not useful enough to warrant
confusing users.

src/buffered-write-sequencer.cc

@@ -31,10 +31,11 @@ struct BufferedWriteSequencer::MemBlock {
 };
 
 BufferedWriteSequencer::BufferedWriteSequencer(
-    int fd, bool allow_frame_skip, int max_queu_len,
+    int fd, bool allow_frame_skip, int max_queu_len, bool debug_no_frame_delay,
     const volatile sig_atomic_t &interrupt_received)
     : fd_(fd), allow_frame_skipping_(allow_frame_skip),
       max_queue_len_(max_queu_len),
+      debug_no_frame_delay_(debug_no_frame_delay),
       interrupt_received_(interrupt_received),
       work_executor_(new std::thread(&BufferedWriteSequencer::ProcessQueue,
                                      this)) {
@@ -144,7 +145,8 @@ void BufferedWriteSequencer::ProcessQueue() {
                 static constexpr Duration kAllowedSkew = Duration::Millis(250);
                 do_skip = (allow_frame_skipping_ &&
                            finish_time + kAllowedSkew < Time::Now());
-                finish_time.WaitUntil();
+                if (!debug_no_frame_delay_)
+                    finish_time.WaitUntil();
             }
             break;
         case SeqType::FrameImmediate:

src/buffered-write-sequencer.h

@@ -50,12 +50,14 @@ class BufferedWriteSequencer {
     // filedescriptor "fd". The "allow_frame_skipping" tells the sequencer
     // if it is ok to skip frames that can't be shown in time anymore.
     // The "max_queue_len" determines the number of the queued-up requests.
+    // If "debug_no_frame_delay" is set, frames are written as fast as possible
+    // without time between frames.
     //
     // Writes that are still pending when the "interrupt_received" flag
     // is set externally (e.g. through a signal handler) are discarded to
     // finish quickly (except ControlWrite calls).
     BufferedWriteSequencer(int fd, bool allow_frame_skipping,
-                           int max_queue_len,
+                           int max_queue_len, bool debug_no_frame_delay,
                            const volatile sig_atomic_t &interrupt_received);
     ~BufferedWriteSequencer();
 
@@ -119,6 +121,7 @@ class BufferedWriteSequencer {
     const int fd_;
     const bool allow_frame_skipping_;
     const size_t max_queue_len_;
+    const bool debug_no_frame_delay_;
     const volatile sig_atomic_t &interrupt_received_;
 
     // Work queue

src/timg.cc

@@ -316,6 +316,7 @@ int main(int argc, char *argv[]) {
     int thread_count = kDefaultThreadCount;
     int geometry_width = (term.cols - 2);
     int geometry_height = (term.rows - 2);
+    bool debug_no_frame_delay = false;
 
     // Convenience predicate: pixelation sending high-res images, no blocks.
     const auto is_pixel_direct_p = [](Pixelation p) {
@@ -326,6 +327,7 @@ int main(int argc, char *argv[]) {
         OPT_CLEAR_SCREEN = 1000,
         OPT_COLOR_256,
         OPT_COMPRESS_PIXEL,
+        OPT_DEBUG_NO_FRAME_DELAY,
         OPT_FRAME_COUNT,
         OPT_FRAME_OFFSET,
         OPT_GRID,
@@ -345,6 +347,7 @@ int main(int argc, char *argv[]) {
         { "color8",      no_argument,       NULL, OPT_COLOR_256 },
         { "compress",    no_argument,       NULL, OPT_COMPRESS_PIXEL },
         { "delta-move",  required_argument, NULL, 'd' },
+        { "debug-no-frame-delay", no_argument, NULL, OPT_DEBUG_NO_FRAME_DELAY },
         { "experimental-frame-offset",required_argument, NULL, OPT_FRAME_OFFSET },
         { "fit-width",   no_argument,       NULL, 'W' },
         { "frames",      required_argument, NULL, OPT_FRAME_COUNT },
@@ -555,6 +558,9 @@ int main(int argc, char *argv[]) {
         case OPT_VERBOSE:
             verbose = true;
             break;
+        case OPT_DEBUG_NO_FRAME_DELAY:
+            debug_no_frame_delay = true;
+            break;
         case 'h':
         default:
             return usage(argv[0], (opt == 'h'
@@ -760,6 +766,7 @@ int main(int argc, char *argv[]) {
     timg::BufferedWriteSequencer sequencer(output_fd,
                                            buffer_allow_skipping,
                                            kAsyncWriteQueueSize,
+                                           debug_no_frame_delay,
                                            interrupt_received);
     const Time start_show = Time::Now();
     PresentImages(loaded_sources, display_opts, present, &sequencer);