"iOS Development-80" quartz2d Drawing Brief Introduction: Line/Circle/ellipse/square and context stack management Cgcontextsavegstate/cgcontextrestoregstate

-(void) DrawRect: (cgrect) Rect {//Get current Context cgcontextref ctx=uigraphicsgetcurrentcontext ();        Save the current context state in the stack cgcontextsavegstate (CTX);    Zoom, move processing (need to be set before drawing) CGCONTEXTSCALECTM (CTX, 0.5, 0.5);    CGCONTEXTTRANSLATECTM (CTX, 100, 100);        CGCONTEXTROTATECTM (CTX, m_pi_4);    Stroke Cgcontextmovetopoint (CTX, 10, 10);    Cgcontextaddlinetopoint (CTX, 100, 100);    Cgcontextaddlinetopoint (CTX, 150, 50);    The following two methods can be closed-loop//cgcontextaddlinetopoint (CTX, 10, 10);    Cgcontextclosepath (CTX);    Render paint, solid and hollow Cgcontextstrokepath (CTX);        Cgcontextfillpath (CTX);        Save the current context state in the stack cgcontextsavegstate (CTX);    Draw a square cgcontextaddrect (CTX, CGRectMake (100, 100, 50, 50)); Set the line width (must be before cgcontextstrokepath)//due to previous rendering of paint, so this property setting does not affect the above triangle, the following color setting is the same//So, false assumption to set two or more properties of the graph, respectively, render the paint once the CG    Contextsetlinewidth (CTX, 10); Set the color (same as.    The code for the property setting is preceded by the drawing code) Cgcontextsetrgbstrokecolor (CTX, 1, 0, 0, 1);        Cgcontextstrokepath (CTX); Set Style CgcontexTmovetopoint (CTX, 20, 160);    Cgcontextaddlinetopoint (CTX, 200, 280);    Cgcontextaddlinetopoint (CTX, 250, 200);    Cgcontextsetlinewidth (CTX, 20);    Set the Kinsoku style Cgcontextsetlinecap (CTX, Kcglinecapround);    Set the corner style Cgcontextsetlinejoin (CTX, Kcglinejoinround);        Cgcontextstrokepath (CTX); Remove the context state stored in the stack and restore it.
 
 
The above code setting style does not affect other cgcontextrestoregstate (CTX);    Draw Oval Cgcontextaddellipseinrect (CTX, CGRectMake (200, 130, 60, 30));    The following equivalent//cgcontextstrokepath (CTX);        Cgcontextdrawpath (CTX, Kcgpathstroke);    Draw round Cgcontextaddellipseinrect (CTX, CGRectMake (140, 170, 50, 50));    Cgcontextsetlinewidth (CTX, 3);        Cgcontextstrokepath (CTX);    Draw Arc Cgcontextaddarc (CTX, M_pi_4, M_PI, 1);        Cgcontextstrokepath (CTX);    Draw 1/4 circles, as well as set new methods of color Cgcontextmovetopoint (CTX, 10, 230);    Cgcontextaddlinetopoint (CTX, 10, 280);    Cgcontextaddlinetopoint (CTX, 60, 280);    Cgcontextaddarc (CTX, ten, 280, 0,-m_pi_2, 1);    [[Uicolor Greencolor] setstroke];        Cgcontextstrokepath (CTX);    Draw pictures and text (without having to manually get the context) NSString *[email protected] "an empty work for the Year of Sin";    [str1 Drawatpoint:cgpointzero Withattributes:nil];    UIImage *img=[uiimage imagenamed:@ "001"];    [img Drawatpoint:cgpointmake (10, 10)];    Overlap The picture in a box and sign CGRect rect1=cgrectmake (50, 50, 100, 100); [IMG Drawaspatterninrect:rect1];    Nsmutabledictionary *attr=[[nsmutabledictionary Alloc]init];    Attr[nsforegroundcolorattributename]=[uicolor Whitecolor];    Attr[nsfontattributename]=[uifont Systemfontofsize:13];        [Str1 Drawinrect:cgrectmake (+, withattributes:attr, +)]; Remove the context state stored in the stack and restore it.        The above code setting style does not affect other cgcontextrestoregstate (CTX);    Crop round head cgcontextaddellipseinrect (CTX, CGRectMake (150, 150, 100, 100));    Cut out a context area according to the Circle, and the later content is filled in the circular context cgcontextclip (CTX);    UIImage *img1=[uiimage imagenamed:@ "Me"]; [Img1 Drawatpoint:cgpointmake (150, 150)];}

"iOS Development-80" quartz2d Drawing Brief Introduction: Line/Circle/ellipse/square and context stack management Cgcontextsavegstate/cgcontextrestoregstate