Android 8.1 关机充电动画（三）Android模式

system：Android 8.1
platform：RK3326/PX30
uboot
kernel
system/core/healthd

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Android 8.1 关机充电动画（一）模式选择
Android 8.1 关机充电动画（二）Uboot模式
Android 8.1 关机充电动画（三）Android模式

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前言

Android模式下的关机充电动画修改相对来说需要修改Linux应用层的东西了，可以定位到源码路径/system/core/healthd下，和uboot模式类似，这里只需要修改轮播的充电图片，然后将每张图片和电量百分比对应到代码中即可，思路还是比较简单的，下面我会慢慢分析具体实现的细节。

文件列表

在system/core/healthd下可以看到以下文件，只有一部分文件需要修改，我们需要重点关注一下healthd_mode_charger.cpp，因为基本上修改这个文件就够了。

Android.mk						11-Jun-2018	5.2 KiB
animation.h						11-Jun-2018	1.7 KiB
AnimationParser.cpp				11-Jun-2018	4.8 KiB
AnimationParser.h				11-Jun-2018	1 KiB
BatteryMonitor.cpp				11-Jun-2018	24 KiB
BatteryPropertiesRegistrar.cpp	11-Jun-2018	4 KiB
BatteryPropertiesRegistrar.h	11-Jun-2018	1.8 KiB
charger.cpp						11-Jun-2018	2.8 KiB
healthd.cpp						11-Jun-2018	3.8 KiB
healthd_common.cpp				11-Jun-2018	8.6 KiB
healthd_draw.cpp				11-Jun-2018	5.7 KiB
healthd_draw.h					11-Jun-2018	2.3 KiB
healthd_mode_android.cpp		11-Jun-2018	2 KiB
healthd_mode_charger.cpp		11-Jun-2018	20.6 KiB
images/							11-Jun-2018	4 KiB
include/						11-Jun-2018	4 KiB
tests/							11-Jun-2018	4 KiB

修改 healthd_mode_charger.cpp

1. 在头文件animation.h的结构体animation添加成员变量user_animation_file，如下所示；

struct animation {
...
	#define USER_IMAGE_NUM 5
	std::string user_animation_file[USER_IMAGE_NUM];
...
}

2. 在healthd_mode_charger.cpp添加frame数组user_animation_frames，目前添加了5帧画面，而且代码里直接固定为5帧的画面为一个充电循环来做，这里后面可能需要改动一下；

static animation::frame user_animation_frames[] = {
    {
        .disp_time = 750,
        .min_level = 0,
        .max_level = 19,
        .surface = NULL,
    },
    {
        .disp_time = 750,
        .min_level = 0,
        .max_level = 39,
        .surface = NULL,
    },
    {
        .disp_time = 750,
        .min_level = 0,
        .max_level = 59,
        .surface = NULL,
    },
    {
        .disp_time = 750,
        .min_level = 0,
        .max_level = 79,
        .surface = NULL,
    },
    {
        .disp_time = 750,
        .min_level = 0,
        .max_level = 100,
        .surface = NULL,
    },
};

init_animation

需要对init_animation函数进行部分的修改，这里简单说明一下；

1. animation_desc_path = "/res/values/charger/animation.txt" ，这里程序中路径具体我也没有找到源码中对应的路径，最终debug的结果是parse_success = false 是一直成立的；所以程序中会直接制定路径下的图片，源码路径system/core/healthd/images/下的图片会在编译的过程中被拷贝到制定的路径下；
2. 原程序的做法只去解析一张png图片，而且这张图片中包含了所有电池电量百分比的对应信息。
3. 修改部分加入到条件编译的宏定义CHARGER_USER_ANIMATION中；

animation* init_animation() {
    bool parse_success;

    std::string content;
    if (base::ReadFileToString(animation_desc_path, &content)) {
        parse_success = parse_animation_desc(content, &battery_animation);
    } else {
        LOGW("Could not open animation description at %s\n", animation_desc_path);
        parse_success = false;
    }
    if (!parse_success) {		
        LOGW("Could not parse animation description. Using default animation.\n");
        battery_animation = BASE_ANIMATION;
#ifdef CHARGER_USER_ANIMATION
		battery_animation.user_animation_file[0].assign("charger/battery_user_0");
		battery_animation.user_animation_file[1].assign("charger/battery_user_1");
		battery_animation.user_animation_file[2].assign("charger/battery_user_2");
		battery_animation.user_animation_file[3].assign("charger/battery_user_3");
		battery_animation.user_animation_file[4].assign("charger/battery_user_4");	
		battery_animation.frames = user_animation_frames;
        battery_animation.num_frames = ARRAY_SIZE(user_animation_frames);
#else
        battery_animation.animation_file.assign("charger/battery_scale");
        battery_animation.frames = default_animation_frames;
		battery_animation.num_frames = ARRAY_SIZE(default_animation_frames);
#endif

    }
    if (battery_animation.fail_file.empty()) {
#ifdef CHARGER_USER_ANIMATION	
		battery_animation.fail_file.assign("charger/battery_user_fail");
#else
        battery_animation.fail_file.assign("charger/battery_fail");
#endif
    }
	if(battery_animation.text_percent.font_file.empty())
	battery_animation.text_percent.font_file.assign("charger/font");
	//battery_animation.text_clock.font_file.assign("charger/font");
    LOGW("Animation Description:\n");
    LOGW("  animation: %d %d '%s' (%d)\n", battery_animation.num_cycles,
         battery_animation.first_frame_repeats, battery_animation.animation_file.c_str(),
         battery_animation.num_frames);
    LOGW("  fail_file: '%s'\n", battery_animation.fail_file.c_str());
    LOGW("  clock: %d %d %d %d %d %d '%s'\n", battery_animation.text_clock.pos_x,
         battery_animation.text_clock.pos_y, battery_animation.text_clock.color_r,
         battery_animation.text_clock.color_g, battery_animation.text_clock.color_b,
         battery_animation.text_clock.color_a, battery_animation.text_clock.font_file.c_str());
    LOGW("  percent: %d %d %d %d %d %d '%s'\n", battery_animation.text_percent.pos_x,
         battery_animation.text_percent.pos_y, battery_animation.text_percent.color_r,
         battery_animation.text_percent.color_g, battery_animation.text_percent.color_b,
         battery_animation.text_percent.color_a, battery_animation.text_percent.font_file.c_str());
    for (int i = 0; i < battery_animation.num_frames; i++) {
        LOGW("  frame %.2d: %d %d %d\n", i, battery_animation.frames[i].disp_time,
             battery_animation.frames[i].min_level, battery_animation.frames[i].max_level);
    }
    return &battery_animation;
}

healthd_mode_charger_init

Android底层的2D引擎库使用了skia，对应的每一帧需要分配GRSurface，通过函数res_create_display_surface分配内存，所以，对于需要定制加入的图片，都需要重新分配内存，然后保存到anim->frames[i].surface中，具体的修改如下所示；

void healthd_mode_charger_init(struct healthd_config* config) {
    int ret;
    charger* charger = &charger_state;
    int i;
    int epollfd;
    dump_last_kmsg();
    LOGW("--------------- STARTING CHARGER MODE ---------------\n");
    ret = ev_init(std::bind(&input_callback, charger, std::placeholders::_1, std::placeholders::_2));
    if (!ret) {
        epollfd = ev_get_epollfd();
        healthd_register_event(epollfd, charger_event_handler, EVENT_WAKEUP_FD);
    }

    animation* anim = init_animation();
    charger->batt_anim = anim;

    ret = res_create_display_surface(anim->fail_file.c_str(), &charger->surf_unknown);
    if (ret < 0) {
        LOGE("Cannot load custom battery_fail image. Reverting to built in.\n");
        ret = res_create_display_surface("charger/battery_fail", &charger->surf_unknown);
        if (ret < 0) {
            LOGE("Cannot load built in battery_fail image\n");
            charger->surf_unknown = NULL;
        }
    }
#ifdef CHARGER_USER_ANIMATION
    GRSurface* scale_frames[USER_IMAGE_NUM];

	for(int i = 0; i<USER_IMAGE_NUM; i++){
		ret = res_create_display_surface(anim->user_animation_file[i].c_str(), &scale_frames[i]);
			if (ret < 0) {
				LOGE("Cannot load custom %s image. Reverting to built in.\n",anim->user_animation_file[i].c_str());
			}else{
				anim->frames[i].surface = scale_frames[i];
				LOGW("file is:[%s],anim->frames[%d].surface = charger->surf_unknown;\n",
					anim->user_animation_file[i].c_str(),i);
			}
	}
#else
	GRSurface** scale_frames
    int scale_count;
    int scale_fps;  // Not in use (charger/battery_scale doesn't have FPS text
                    // chunk). We are using hard-coded frame.disp_time instead.

	ret = res_create_multi_display_surface(anim->animation_file.c_str(), &scale_count, &scale_fps,
											   &scale_frames);
		if (ret < 0) {
			LOGE("Cannot load battery_scale image\n");
			anim->num_frames = 0;
			anim->num_cycles = 1;
		} else if (scale_count != anim->num_frames) {
			LOGE("battery_scale image has unexpected frame count (%d, expected %d)\n", scale_count,
				 anim->num_frames);
			anim->num_frames = 0;
			anim->num_cycles = 1;
		} else {
			for (i = 0; i < anim->num_frames; i++) {
				anim->frames[i].surface = scale_frames[i];
			}
		}
#endif
    ev_sync_key_state(
        std::bind(&set_key_callback, charger, std::placeholders::_1, std::placeholders::_2));
    charger->next_screen_transition = -1;
    charger->next_key_check = -1;
    charger->next_pwr_check = -1;
    healthd_config = config;
    charger->boot_min_cap = config->boot_min_cap;
}

替换图片

把图片复制到/system/core/healthd/images/路径下，注意图片格式需要是png，而且图片保存的位深度为8位，文件名需要和程序中定义的路径变量保持一致即可；如下所示；我简单地切了五张图片，感觉切图的时间比debug的时间还要久。苦。

然后，在Android.mk中可找到，在编译的时候对图片进行了打包，相应的命令如下所示；

...
 _img_modules :=
 _images :=
 $(foreach _img, $(call find-subdir-subdir-files, "images", "*.png"), \
   $(eval $(call _add-charger-image,$(_img))))
...

完成以上这些步骤之后，重新编译Android系统，当然还需要进入关机充电的Android模式，可以发现充电动画已经修改完了。

总结

这里介绍的是比较简单对充电动画的单帧图片进行替换，如果有更加复杂的需求，还需要在healthd_draw.cpp进行修改，或者更高级可以自己画充电动画出来也未尝不可。