Fix 745 by improving the draw_annotations() block drawing algo

diff --git a/pv/view/decodetrace.cpp b/pv/view/decodetrace.cpp
index e0f3a0f262734509dadd3d412a920fb2dfe789fc..e7ffbbb6acd361e9f44749cad1ea80d413049c5c 100644 (file)
--- a/pv/view/decodetrace.cpp
+++ b/pv/view/decodetrace.cpp
@@ -337,33 +337,63 @@ void DecodeTrace::draw_annotations(vector<pv::data::decode::Annotation> annotati
        using namespace pv::data::decode;
 
        vector<Annotation> a_block;
-       int prev_ann_pos = INT_MIN;
+       int p_end = INT_MIN;
 
        double samples_per_pixel, pixels_offset;
        tie(pixels_offset, samples_per_pixel) =
                get_pixels_offset_samples_per_pixel();
 
+       // Sort the annotations by start sample so that decoders
+       // can't confuse us by creating annotations out of order
+       stable_sort(annotations.begin(), annotations.end(),
+               [](const Annotation &a, const Annotation &b) {
+                       return a.start_sample() < b.start_sample(); });
+
        // Gather all annotations that form a visual "block" and draw them as such
        for (const Annotation &a : annotations) {
 
-               const int end = a.end_sample() / samples_per_pixel - pixels_offset;
-               const int delta = end - prev_ann_pos;
+               const int a_start = a.start_sample() / samples_per_pixel - pixels_offset;
+               const int a_end = a.end_sample() / samples_per_pixel - pixels_offset;
+               const int a_width = a_end - a_start;
+
+               const int delta = a_end - p_end;
+
+               bool a_is_separate = false;
+
+               // Annotation wider than the threshold for a useful label width?
+               if (a_width > 20) {
+                       for (const QString &ann_text : a.annotations()) {
+                               const int w = p.boundingRect(QRectF(), 0, ann_text).width();
+                               // Annotation wide enough to fit a label? Don't put it in a block then
+                               if (w <= a_width) {
+                                       a_is_separate = true;
+                                       break;
+                               }
+                       }
+               }
 
-               // Some annotations are in reverse order, so we cannot
-               // simply check for delta > 1
-               if (abs(delta) > 1) {
-                       // Block was broken, draw it
-                       if (a_block.size() == 1)
+               // Were the previous and this annotation more than a pixel apart?
+               if ((abs(delta) > 1) || a_is_separate) {
+                       // Block was broken, draw annotations that form the current block
+                       if (a_block.size() == 1) {
                                draw_annotation(a_block.front(), p, h, pp, y, base_colour);
+                       }
                        else
-                               if (a_block.size() > 0)
-                                       draw_annotation_block(a_block, p, h, y, base_colour);
+                               draw_annotation_block(a_block, p, h, y, base_colour);
 
                        a_block.clear();
                }
 
-               a_block.push_back(a);
-               prev_ann_pos = end;
+               if (a_is_separate) {
+                       draw_annotation(a, p, h, pp, y, base_colour);
+                       // Next annotation must start a new block. delta will be > 1
+                       // because we set p_end to INT_MIN but that's okay since
+                       // a_block will be empty, so nothing will be drawn
+                       p_end = INT_MIN;
+               } else {
+                       a_block.push_back(a);
+                       p_end = a_end;
+               }
        }
 
        if (a_block.size() == 1)
@@ -404,6 +434,9 @@ void DecodeTrace::draw_annotation_block(
 {
        using namespace pv::data::decode;
 
+       if (annotations.empty())
+               return;
+
        double samples_per_pixel, pixels_offset;
        tie(pixels_offset, samples_per_pixel) =
                get_pixels_offset_samples_per_pixel();