uCGUI字符串显示过程分析

 1 void GUI_DispString(const char GUI_UNI_PTR *s) {
 2   int xAdjust, yAdjust, xOrg;
 3   int FontSizeY;
 4   if (!s)
 5     return;
 6   GUI_LOCK();
 7   FontSizeY = GUI_GetFontDistY();         //获取字体的高度
 8   xOrg = GUI_Context.DispPosX;            //获取当前显示的x坐标
 9  /* Adjust vertical position */
10   yAdjust = GUI_GetYAdjust();                    
11   GUI_Context.DispPosY -= yAdjust;        //根据Y方向上的对齐方式对y进行调整
12   for (; *s; s++) {
13     GUI_RECT r;
14     int LineNumChars = GUI__GetLineNumChars(s, 0x7fff);           //当前一行要显示几个字符
15     int xLineSize    = GUI__GetLineDistX(s, LineNumChars);        //当前一行在x方向上的像素数
16   /* Check if x-position needs to be changed due to h-alignment */
17     switch (GUI_Context.TextAlign & GUI_TA_HORIZONTAL) {
18       case GUI_TA_CENTER: xAdjust = xLineSize / 2; break;
19       case GUI_TA_RIGHT:  xAdjust = xLineSize; break;
20       default:            xAdjust = 0;
21     }
22     /* 计算出每一行显示内容的矩形区域 */
23     r.x0 = GUI_Context.DispPosX -= xAdjust;          //根据水平方向的对齐方式对x坐标进行调整
24     r.x1 = r.x0 + xLineSize - 1;    
25     r.y0 = GUI_Context.DispPosY;
26     r.y1 = r.y0 + FontSizeY - 1;
27         
28     GUI__DispLine(s, LineNumChars, &r);              //以计算好的矩形区域显示当前行字符
29     GUI_Context.DispPosY = r.y0;
30     s += GUI_UC__NumChars2NumBytes(s, LineNumChars); //从第一个字符开始，地址加1，可以遍历整行字符串
31     if ((*s == ‘\n‘) || (*s == ‘\r‘)) {
32       switch (GUI_Context.TextAlign & GUI_TA_HORIZONTAL) { 
33       case GUI_TA_CENTER:
34       case GUI_TA_RIGHT:
35         GUI_Context.DispPosX = xOrg;
36         break;
37       default:
38         GUI_Context.DispPosX = GUI_Context.LBorder;
39         break;
40       }
41       if (*s == ‘\n‘)
42         GUI_Context.DispPosY += FontSizeY;
43     } else {
44       GUI_Context.DispPosX = r.x0 + xLineSize;
45     }
46     if (*s == 0)    /* end of string (last line) reached ? */
47       break;
48   }
49   GUI_Context.DispPosY += yAdjust;                //
50   GUI_Context.TextAlign &= ~GUI_TA_HORIZONTAL;    //
51   GUI_UNLOCK();
52 }

struct GUI_CONTEXT {
/* Variables in LCD module */
  LCD_COLORINDEX_UNION LCD;
  LCD_RECT       ClipRect;
  U8             DrawMode;
  U8             SelLayer;
  U8             TextStyle;
/* Variables in GL module */
  GUI_RECT* pClipRect_HL;                /* High level clip rectangle ... Speed optimization so drawing routines can optimize */
  U8        PenSize;
  U8        PenShape;
  U8        LineStyle;
  U8        FillStyle;
/* Variables in GUICHAR module */
  const GUI_FONT           GUI_UNI_PTR * pAFont;  //指向当前选择的字体
  #if GUI_SUPPORT_UNICODE
    const GUI_UC_ENC_APILIST * pUC_API;    /* Unicode encoding API */
  #endif
  I16P LBorder;
  I16P DispPosX, DispPosY;
  I16P DrawPosX, DrawPosY;
  I16P TextMode, TextAlign;                       //对齐方式
  GUI_COLOR Color, BkColor;           /* Required only when changing devices and for speed opt (caching) */
/* Variables in WM module */
  #if GUI_WINSUPPORT
    const GUI_RECT* WM__pUserClipRect;
    GUI_HWIN hAWin;
    int xOff, yOff;
  #endif
/* Variables in MEMDEV module (with memory devices only) */
  #if GUI_SUPPORT_DEVICES
    const tLCDDEV_APIList* pDeviceAPI;  /* function pointers only */
    GUI_HMEM    hDevData;
    GUI_RECT    ClipRectPrev;
  #endif
/* Variables in Anitaliasing module */
  #if GUI_SUPPORT_AA
    const tLCD_HL_APIList* pLCD_HL;     /* Required to reroute drawing (HLine & Pixel) to the AA module */
    U8 AA_Factor;
    U8 AA_HiResEnable;
  #endif
};

struct GUI_FONT {
  GUI_DISPCHAR*     pfDispChar;             //显示一个属于当前字库字符的函数
  GUI_GETCHARDISTX* pfGetCharDistX;         //获取字库中某字符的宽度
  GUI_GETFONTINFO*  pfGetFontInfo;          //获取字库信息
  GUI_ISINFONT*     pfIsInFont;             //查询字库中是否存在此字符
  const tGUI_ENC_APIList* pafEncode;        //
  U8 YSize;                        //高度
  U8 YDist;                        //对应的像素点
  U8 XMag;                         //X方向上的放大系数
  U8 YMag;                         //Y方向上的放大系数
  union {                          //此共用体主要是提供字库数据的访问地址，
                                   //对于不同的字库，其从字库中查找字模的方法，是不一样的
                                   //这里主要分成三种情况，对应三种类型的指针        
    const void          GUI_UNI_PTR * pFontData;
    const GUI_FONT_MONO GUI_UNI_PTR * pMono;
    const GUI_FONT_PROP GUI_UNI_PTR * pProp;
  } p;
  U8 Baseline;                                //
  U8 LHeight;     /* height of a small lower case character (a,x) */    //小写高度
  U8 CHeight;     /* height of a small upper case character (A,X) */    //大写高度
};