67 lines
2.9 KiB
C++
67 lines
2.9 KiB
C++
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "webp/encode.h" // WebP 头文件，用于编码 WebP
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#include "stb_image.h" // stb_image 头文件，用于解码 PNG/JPG
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#define STB_IMAGE_RESIZE_IMPLEMENTATION
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#include "stb_image_resize.h"
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extern "C" {
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// 将输入的 JPG/PNG 数据转换为 WebP，并返回 WebP 数据
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unsigned char *convert_image_to_webp(const uint8_t *input_data, size_t input_size, int target_width, int target_height, float quality_factor, size_t *output_size, int preserve_alpha = 0) {
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int width, height, channels;
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// 使用 stb_image 解码输入图像（根据 preserve_alpha 决定加载通道数）
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unsigned char *decoded_data = stbi_load_from_memory(input_data, input_size, &width, &height, &channels, preserve_alpha ? 4 : 3); // 根据是否保留 alpha 通道加载
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if (!decoded_data) {
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return nullptr; // 图像解码失败
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}
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// 如果需要调整尺寸，则进行调整
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unsigned char *resized_data = decoded_data;
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if (target_width > 0 && target_height > 0) {
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// 分配用于存储调整大小后图像的缓冲区
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resized_data = (unsigned char *)malloc(target_width * target_height * (preserve_alpha ? 4 : 3)); // 根据是否保留 alpha 通道调整缓冲区大小
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if (!resized_data) {
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// 内存分配失败的处理
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fprintf(stderr, "Failed to allocate memory for resized image.\n");
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stbi_image_free(decoded_data); // 释放原始解码数据
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return NULL;
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}
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// 使用 stb_image_resize 调整图像大小
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int result = stbir_resize_uint8(decoded_data, width, height, 0,
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resized_data, target_width, target_height, 0, preserve_alpha ? 4 : 3);
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if (!result) {
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// 如果调整大小失败，释放已分配的内存
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fprintf(stderr, "Image resizing failed.\n");
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free(resized_data);
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stbi_image_free(decoded_data);
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return NULL;
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}
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} else {
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target_width = width;
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target_height = height;
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}
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// 使用 libwebp 的有损编码函数（WebPEncodeRGB）将 RGB 图像编码为 WebP
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unsigned char *webp_output = NULL;
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if (preserve_alpha) {
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*output_size = WebPEncodeRGBA(resized_data, target_width, target_height, target_width * 4, quality_factor, &webp_output);
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} else {
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*output_size = WebPEncodeRGB(resized_data, target_width, target_height, target_width * 3, quality_factor, &webp_output);
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}
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// 释放解码后的图像内存
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stbi_image_free(decoded_data);
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if (resized_data != decoded_data) {
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free(resized_data); // 如果调整了大小，则释放调整大小后的数据
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}
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return webp_output; // 返回 WebP 编码后的数据
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}
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} |