6.6.3 - Alpha5 - images.save 方法使用 quality 参数时支持 png 格式的文件体积压缩 (issue #367)

2025-05-18 12:08:33 +08:00
parent 0882cf4166
commit 676dde9632
89 changed files with 47124 additions and 58 deletions
--- a/libs/imagequant/PngQuantBridge.cpp
+++ b/libs/imagequant/PngQuantBridge.cpp
@@ -0,0 +1,159 @@
+#include <jni.h>
+#include <vector>
+#include "libimagequant.h"
+#include "png.h"
+#include <android/log.h>
+
+#define ALOGE(fmt, ...) __android_log_print(ANDROID_LOG_ERROR, "PNGQ", fmt, ##__VA_ARGS__)
+
+extern "C"
+JNIEXPORT jbyteArray JNICALL
+Java_org_autojs_autojs_runtime_api_PngQuantBridge_quantize(
+        JNIEnv *env, jclass, jbyteArray srcRgba,
+        jint width, jint height, jint quality) {
+
+    /* 读取像素. */
+
+    jsize len = env->GetArrayLength(srcRgba);
+    std::vector<uint8_t> rgba(len);
+    env->GetByteArrayRegion(srcRgba, 0, len, reinterpret_cast<jbyte *>(rgba.data()));
+
+    if (len != width * height * 4) {
+        ALOGE("rgba length mismatch, len=%d, expect=%d", len, width * height * 4);
+        return nullptr;
+    }
+
+    /* libimagequant 量化. */
+
+    liq_attr *attr = liq_attr_create();
+    if (!attr) {
+        ALOGE("liq_attr_create failed");
+        return nullptr;
+    }
+
+    liq_set_speed(attr, 8);
+    liq_set_quality(attr, quality, quality);
+    liq_set_max_colors(attr, 256);
+
+    liq_image *image = liq_image_create_rgba(attr, rgba.data(), width, height, 0);
+    liq_result *res;
+
+    liq_error err = liq_image_quantize(image, attr, &res);
+    if (err != LIQ_OK) {
+        ALOGE("liq_image_quantize failed, code=%d", err);
+        liq_image_destroy(image);
+        liq_attr_destroy(attr);
+        return nullptr;
+    }
+
+    size_t outSize = width * height;
+    std::vector<uint8_t> indexed(outSize);
+    liq_write_remapped_image(res, image, indexed.data(), outSize);
+    const liq_palette *pal = liq_get_palette(res);
+
+    /* 写索引色 PNG 到内存. */
+
+    std::vector<uint8_t> compressed;
+    do {
+        /* palette 检查. */
+        if (!pal || pal->count == 0 || pal->count > 256) {
+            ALOGE("invalid palette count=%d", pal ? pal->count : -1);
+            goto png_fail;
+        }
+
+        /* libpng 结构体. */
+        png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+            nullptr,
+            [](png_structp png_ptr, png_const_charp msg) {
+                ALOGE("libpng error: %s", msg);
+                longjmp(png_jmpbuf(png_ptr), 1);
+            },
+            nullptr);
+        if (!png_ptr) {
+            ALOGE("png_create_write_struct failed");
+            goto png_fail;
+        }
+
+        png_infop info_ptr = png_create_info_struct(png_ptr);
+        if (!info_ptr) {
+            png_destroy_write_struct(&png_ptr, nullptr);
+            goto png_fail;
+        }
+
+        /* longjmp error handler. */
+        if (setjmp(png_jmpbuf(png_ptr))) {
+            png_destroy_write_struct(&png_ptr, &info_ptr);
+            goto png_fail;
+        }
+
+        /* custom mem writer. */
+        struct Writer {
+            static void PNGAPI write(png_structp png_ptr, png_bytep data, png_size_t len) {
+                auto *vec = static_cast<std::vector<uint8_t> *>(png_get_io_ptr(png_ptr));
+                vec->insert(vec->end(), data, data + len);
+            }
+            static void PNGAPI flush(png_structp) {}
+        };
+        std::vector<uint8_t> tmpBuf;
+        png_set_write_fn(png_ptr, &tmpBuf, Writer::write, Writer::flush);
+
+        /* IHDR. */
+        png_set_IHDR(png_ptr, info_ptr,
+                    static_cast<png_uint_32>(width),
+                    static_cast<png_uint_32>(height),
+                    8,                              // bit depth
+                    PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
+                    PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+        png_set_compression_level(png_ptr, 3);
+        png_set_filter(png_ptr, 0, PNG_FILTER_NONE);
+
+        /* PLTE & tRNS. */
+        png_color plte[256];
+        png_byte trns[256];
+        int num_trns = 0;
+        for (int i = 0; i < pal->count; ++i) {
+            plte[i].red = pal->entries[i].r;
+            plte[i].green = pal->entries[i].g;
+            plte[i].blue = pal->entries[i].b;
+            trns[i] = pal->entries[i].a;
+            if (trns[i] < 255) num_trns = i + 1;
+        }
+        png_set_PLTE(png_ptr, info_ptr, plte, pal->count);
+        if (num_trns) png_set_tRNS(png_ptr, info_ptr, trns, num_trns, nullptr);
+
+        png_write_info(png_ptr, info_ptr);
+
+        /* rows. */
+        std::vector<png_bytep> rows(height);
+        for (int y = 0; y < height; ++y) {
+            rows[y] = indexed.data() + y * width;
+        }
+        png_write_image(png_ptr, rows.data());
+
+        png_write_end(png_ptr, info_ptr);
+        compressed.swap(tmpBuf);
+
+        /* 无论是否成功, 均销毁. */
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+    } while (false);
+
+png_fail:
+    if (compressed.empty()) {
+        ALOGE("compress failed, return null to Java");
+        env->ThrowNew(env->FindClass("java/io/IOException"),
+                    "pngquant native: compress failed");
+        return nullptr;
+    }
+
+    /* 清理. */
+    liq_result_destroy(res);
+    liq_image_destroy(image);
+    liq_attr_destroy(attr);
+
+    /* 回 JNI. */
+    jbyteArray out = env->NewByteArray(compressed.size());
+    env->SetByteArrayRegion(out, 0, compressed.size(),
+                         reinterpret_cast<jbyte *>(compressed.data()));
+    return out;
+}