Use ListBox for slide picker in Viewer

Interaction is much nicer (the bulleted list of text had dead space
between entries, so mouse clicks could go unnoticed). This version also
keeps the currently active slide highlighted in the list, which is nice.

Bug: skia:
Change-Id: I609d90f3b1ff99765f0a7f1ca43e02a0a534dc4d
Reviewed-on: https://skia-review.googlesource.com/68780
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

1 files changed, 19 insertions, 11 deletions

diff --git a/tools/viewer/Viewer.cpp b/tools/viewer/Viewer.cpp
index 03b774804f..220a482805 100644
--- a/tools/viewer/Viewer.cpp
+++ b/tools/viewer/Viewer.cpp
@@ -1180,21 +1180,29 @@ void Viewer::drawImGui(SkCanvas* canvas) {
 
             if (ImGui::CollapsingHeader("Slide")) {
                 static ImGuiTextFilter filter;
+                static ImVector<const char*> filteredSlideNames;
+                static ImVector<int> filteredSlideIndices;
+
                 filter.Draw();
-                int previousSlide = fCurrentSlide;
-                fCurrentSlide = 0;
-                for (auto slide : fSlides) {
-                    if (filter.PassFilter(slide->getName().c_str())) {
-                        ImGui::BulletText("%s", slide->getName().c_str());
-                        if (ImGui::IsItemClicked()) {
-                            setupCurrentSlide(previousSlide);
-                            break;
+                filteredSlideNames.clear();
+                filteredSlideIndices.clear();
+                int filteredIndex = 0;
+                for (int i = 0; i < fSlides.count(); ++i) {
+                    const char* slideName = fSlides[i]->getName().c_str();
+                    if (filter.PassFilter(slideName) || i == fCurrentSlide) {
+                        if (i == fCurrentSlide) {
+                            filteredIndex = filteredSlideIndices.size();
                         }
+                        filteredSlideNames.push_back(slideName);
+                        filteredSlideIndices.push_back(i);
                     }
-                    ++fCurrentSlide;
                 }
-                if (fCurrentSlide >= fSlides.count()) {
-                    fCurrentSlide = previousSlide;
+
+                int previousSlide = fCurrentSlide;
+                if (ImGui::ListBox("", &filteredIndex, filteredSlideNames.begin(),
+                                   filteredSlideNames.size(), 20)) {
+                    fCurrentSlide = filteredSlideIndices[filteredIndex];
+                    setupCurrentSlide(previousSlide);
                 }
             }