lottie: add lottie audio sample

src/LottieAudio.cpp

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2026 ThorVG project. All rights reserved.
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#define MINIAUDIO_IMPLEMENTATION
+#include "miniaudio.h"
+
+#include <thorvg-1/thorvg_lottie.h>
+#include "Example.h"
+
+
+/************************************************************************/
+/* ThorVG Drawing Contents                                              */
+/************************************************************************/
+
+struct UserExample : tvgexam::Example
+{
+    unique_ptr<tvg::LottieAnimation> lottie;
+
+    ma_engine  engine;
+    ma_decoder decoder;
+    ma_sound   sound;
+    bool engineReady  = false;
+    bool decoderReady = false;
+    bool soundReady   = false;
+    float prevProgress = 0.0f;
+
+    ~UserExample()
+    {
+        if (soundReady)   ma_sound_uninit(&sound);
+        if (decoderReady) ma_decoder_uninit(&decoder);
+        if (engineReady)  ma_engine_uninit(&engine);
+    }
+
+    void onAudio(const tvg::AudioInfo& info)
+    {
+        if (info.active) {
+            //lazy-init the sound from embedded audio bytes
+            if (!soundReady && !info.path && info.src && info.size > 0) {
+                if (ma_decoder_init_memory(info.src, info.size, nullptr, &decoder) == MA_SUCCESS) {
+                    decoderReady = true;
+                    auto flags = MA_SOUND_FLAG_DECODE | MA_SOUND_FLAG_NO_SPATIALIZATION;
+                    soundReady = (ma_sound_init_from_data_source(&engine, &decoder, flags, nullptr, &sound) == MA_SUCCESS);
+                }
+            }
+
+            if (soundReady) {
+                auto sr = ma_engine_get_sample_rate(&engine);
+                ma_sound_seek_to_pcm_frame(&sound, static_cast<ma_uint64>(info.offset * sr));
+                ma_sound_set_volume(&sound, info.volume);
+                ma_sound_start(&sound);
+            }
+        } else if (soundReady) {
+            ma_sound_stop(&sound);
+        }
+    }
+
+    bool content(tvg::Canvas* canvas, uint32_t w, uint32_t h) override
+    {
+        if (ma_engine_init(nullptr, &engine) != MA_SUCCESS) return false;
+        engineReady = true;
+
+        //background
+        auto* bg = tvg::Shape::gen();
+        bg->appendRect(0, 0, w, h);
+        bg->fill(30, 30, 35);
+        canvas->add(bg);
+
+        //lottie animation
+        lottie = unique_ptr<tvg::LottieAnimation>(tvg::LottieAnimation::gen());
+        auto* pic = lottie->picture();
+        if (!tvgexam::verify(pic->load(EXAMPLE_DIR"/lottie/emoji_audio.json"))) return false;
+
+        float pw, ph;
+        pic->size(&pw, &ph);
+        auto scale = (pw / ph > float(w) / h) ? float(w) / pw : float(h) / ph;
+        pic->scale(scale);
+        pic->translate((w - pw * scale) * 0.5f, (h - ph * scale) * 0.5f);
+        canvas->add(pic);
+
+        //register the audio resolver
+        lottie->audioResolver([this](const tvg::AudioInfo& info, void*) { onAudio(info); }, nullptr);
+
+        return true;
+    }
+
+    bool update(tvg::Canvas* canvas, uint32_t elapsed) override
+    {
+        auto progress = tvgexam::progress(elapsed, lottie->duration());
+
+        if (progress < prevProgress && soundReady) {
+            ma_sound_seek_to_pcm_frame(&sound, 0);
+            ma_sound_start(&sound);
+        }
+        prevProgress = progress;
+
+        lottie->frame(lottie->totalFrame() * progress);
+
+        canvas->update();
+        return true;
+    }
+};
+
+
+/************************************************************************/
+/* Entry Point                                                          */
+/************************************************************************/
+
+int main(int argc, char **argv)
+{
+    return tvgexam::main(new UserExample, argc, argv, false, 1024, 600, 0);
+}

src/meson.build

@@ -97,15 +97,41 @@ lottie_example = '''
     }
 '''
 
+audio_dep = declare_dependency()
+
 if cc.links(lottie_example, dependencies : thorvg_dep, include_directories : thorvg_inc)
     source_file += [
         'Lottie.cpp',
+        'LottieAudio.cpp',
         'LottieExpressions.cpp',
         'LottieExtension.cpp',
         'LottieInteraction.cpp',
         'LottieBigSize.cpp',
         'LottieTweening.cpp'
     ]
+
+    # LottieAudio backend (miniaudio)
+    audio_link_args = []
+    if host_machine.system() == 'darwin'
+        audio_link_args += ['-framework', 'CoreAudio', '-framework', 'CoreFoundation', '-framework', 'AudioToolbox']
+    elif host_machine.system() == 'linux'
+        audio_link_args += ['-ldl', '-lpthread', '-lm']
+        alsa_dep = dependency('alsa', required: false)
+        if alsa_dep.found()
+            audio_link_args += ['-lasound']
+        else
+            pulse_dep = dependency('libpulse', required: false)
+            if pulse_dep.found()
+                audio_link_args += ['-lpulse']
+            endif
+        endif
+    elif host_machine.system() == 'windows'
+        audio_link_args += ['-lole32', '-lwinmm']
+    endif
+    audio_dep = declare_dependency(
+        link_args           : audio_link_args,
+        include_directories : include_directories('../vendor'))
+
     message('ThorVG Lottie found. Enabled Lottie examples.')
 else
     message('ThorVG Lottie not found. Skipping Lottie examples.')
@@ -121,8 +147,12 @@ endif
 
 foreach current_file : source_file
     name = current_file.split('.')[0]
+    deps = examples_dep
+    if name == 'LottieAudio'
+        deps += audio_dep
+    endif
     executable(name, current_file,
-        dependencies: examples_dep,
+        dependencies: deps,
         cpp_args : compiler_flags)
 endforeach