void ScreenRecoveryUI::Init()
{
gr_init();
gr_font_size(&char_width, &char_height);
text_col = text_row = 0;
text_rows = gr_fb_height() / char_height;
if (text_rows > kMaxRows) text_rows = kMaxRows;
text_top = 1;
text_cols = gr_fb_width() / char_width;
if (text_cols > kMaxCols - 1) text_cols = kMaxCols - 1;
LoadBitmap("icon_installing", &backgroundIcon[INSTALLING_UPDATE]);
backgroundIcon[ERASING] = backgroundIcon[INSTALLING_UPDATE];
LoadBitmap("icon_error", &backgroundIcon[ERROR]);
backgroundIcon[NO_COMMAND] = backgroundIcon[ERROR];
LoadBitmap("progress_empty", &progressBarEmpty);
LoadBitmap("progress_fill", &progressBarFill);
LoadLocalizedBitmap("installing_text", &backgroundText[INSTALLING_UPDATE]);
LoadLocalizedBitmap("erasing_text", &backgroundText[ERASING]);
LoadLocalizedBitmap("no_command_text", &backgroundText[NO_COMMAND]);
LoadLocalizedBitmap("error_text", &backgroundText[ERROR]);
int i;
progressBarIndeterminate = (gr_surface*)malloc(indeterminate_frames *
sizeof(gr_surface));
for (i = 0; i 0) {
installationOverlay = (gr_surface*)malloc(installing_frames *
sizeof(gr_surface));
for (i = 0; i
1、gr_init() 初始化圖形裝置，配置設定Pixelflinger庫渲染的記憶體
2、gr_font_size() 将字型對應的surface長寬指派給char_width和char_height
3、LoadBitmap() 将png生成surface, 每個png圖檔對應一個surface, 所有surface存放在一個數組中
4、LoadLocalizedBitmap() 将區域文字所在的圖檔中的text資訊根據目前的locale提取出來，生成對應的surface, 是以
surface也存放在一個數組中
6、pthread_create(&progress_t, NULL, progress_thread, NULL)
建立一個線程，該線程的任務是一個死循環，在該循環中不停
地檢測currentIcon以及progressBarType來決定是不是要更新進度條。
7、調用RecoveryUI的Init()，初始化輸入事件處理。
void ScreenRecoveryUI::SetLocale(const char* locale) {
if (locale) {
char* lang = strdup(locale);
for (char* p = lang; *p; ++p) {
if (*p == '_') {
*p = '\0';
break;
}
}
// A bit cheesy: keep an explicit list of supported languages
// that are RTL.
if (strcmp(lang, "ar") == 0 || // Arabic
strcmp(lang, "fa") == 0 || // Persian (Farsi)
strcmp(lang, "he") == 0 || // Hebrew (new language code)
strcmp(lang, "iw") == 0 || // Hebrew (old language code)
strcmp(lang, "ur") == 0) { // Urdu
rtl_locale = true;
}
free(lang);
}
}
ScreenRecoveryUI類的SetLocale， 該函數根據locale判斷所用的字型是否屬于阿拉伯語系，阿拉伯語的書寫習慣是從右到左，如果是阿拉伯語系的話，就設定一個标志，後面根據這個标志決定從右到左顯示文字或進度條。SetLocale的參數locale指派邏輯是這樣的，先從command檔案中讀取, command檔案中設定locale的指令如"--locale=zh_CN“，如果沒有傳入locale,初始化過程中會嘗試從/cache/recovery/last_locale中讀取locale, 如果該檔案也沒有，則locale不會被指派，就預設用English. void ScreenRecoveryUI::SetBackground(Icon icon)
{
pthread_mutex_lock(&updateMutex);
// Adjust the offset to account for the positioning of the
// base image on the screen.
if (backgroundIcon[icon] != NULL) {
gr_surface bg = backgroundIcon[icon];
gr_surface text = backgroundText[icon];
overlay_offset_x = install_overlay_offset_x + (gr_fb_width() - gr_get_width(bg)) / 2;
overlay_offset_y = install_overlay_offset_y +
(gr_fb_height() - (gr_get_height(bg) + gr_get_height(text) + 40)) / 2;
}
currentIcon = icon;
update_screen_locked();
pthread_mutex_unlock(&updateMutex);
} SetBackground函數比較簡潔，關鍵部分在update_screen_locked，下面我們重點分析一下。 update_screen_locked和update_progress_locked是recovery的UI部分的關鍵函數，update_screen_locked用來更新背景, update_progress_locked用來更新進度條，因為顯示的畫面會一直在更新，是以這兩個函數會在不同的地方被反複調用
void ScreenRecoveryUI::update_screen_locked()
{
draw_screen_locked();
gr_flip();
} update_screen_locked包含兩個操作，一是更新screen, 二是切換前後buffer。 void ScreenRecoveryUI::draw_screen_locked()
{
draw_background_locked(currentIcon);
draw_progress_locked();
if (show_text) {
SetColor(TEXT_FILL);
gr_fill(0, 0, gr_fb_width(), gr_fb_height());
int y = 0;
int i = 0;
if (show_menu) {
SetColor(HEADER);
for (; i y+2 && count
draw_background_locked函數的實作代碼中又出現了幾個以gr_開頭的函數，以gr_開頭的函數來自minui庫，minui庫的代碼在recovery源碼下的minui目錄下，minui提供的接口實作了圖形的描繪以及固定大小的文字顯示。
gr_color(unsigned char r, unsigned char g, unsigned char b, unsigned char a);
gr_fill(int x, int y, int w, int h);
gr_blit(gr_surface source, int sx, int sy, int w, int h, int dx, int dy);
draw_background_locked函數先将整個渲染buffer填充為黑色，然後計算背景surface的長寬，文字surface的長寬，再結合fb的長寬計算出背景surface以及文字surface顯示的坐标，有長寬和坐标就可以調用Pixelflinger的接口在渲染buffer上進行渲染。
void ScreenRecoveryUI::draw_progress_locked()
{
if (currentIcon == ERROR) return;
if (currentIcon == INSTALLING_UPDATE || currentIcon == ERASING) {
draw_install_overlay_locked(installingFrame);
}
if (progressBarType != EMPTY) {
int iconHeight = gr_get_height(backgroundIcon[INSTALLING_UPDATE]);
int width = gr_get_width(progressBarEmpty);
int height = gr_get_height(progressBarEmpty);
int dx = (gr_fb_width() - width)/2;
int dy = (3*gr_fb_height() + iconHeight - 2*height)/4;
// Erase behind the progress bar (in case this was a progress-only update)
gr_color(0, 0, 0, 255);
gr_fill(dx, dy, width, height);
if (progressBarType == DETERMINATE) {
float p = progressScopeStart + progress * progressScopeSize;
int pos = (int) (p * width);
if (rtl_locale) {
// Fill the progress bar from right to left.
if (pos > 0) {
gr_blit(progressBarFill, width-pos, 0, pos, height, dx+width-pos, dy);
}
if (pos 0) {
gr_blit(progressBarFill, 0, 0, pos, height, dx, dy);
}
if (pos
draw_progress_locked函數的原理與 update_screen_locked函數類似， 最終是将進度條的surface輸出到渲染buffer,
recovery中各個場景的畫面，就是由背景、文字、進度條的重疊，不同的是所用的surface 以及surface的坐标。
recovery main函數中的UI代碼基本上已經分析過了，最後一點主菜單的顯示，就是通過上面介紹的這些接口将文字圖檔顯示出來，是以就不再多講。總的來說，recovery的UI顯示部分難度不大，應用層調用minui庫實作了圖形的描繪以及固定大小的文字顯示，minui庫調用了Pixelflinger庫來進行渲染。
附上minui部分接口的說明，供參考
int gr_init(void);
void gr_exit(void);
int gr_fb_width(void);
int gr_fb_height(void);
gr_pixel *gr_fb_data(void);
void gr_flip(void);
void gr_fb_blank(bool blank);
void gr_color(unsigned char r, unsigned char g, unsigned char b, unsigned char a);
void gr_fill(int x, int y, int w, int h);
int gr_text(int x, int y, const char *s);
int gr_measure(const char *s);
void gr_font_size(int *x, int *y);
void gr_blit(gr_surface source, int sx, int sy, int w, int h, int dx, int dy);
unsigned int gr_get_width(gr_surface surface);
unsigned int gr_get_height(gr_surface surface);
int res_create_surface(const char* name, gr_surface* pSurface);
void res_free_surface(gr_surface surface);