Core Graphics Learning Note Image Drawing (ii)

Source: Internet
Author: User

1. Three ways to draw arrows

  Drawing code//cgcontextref con = uigraphicsgetcurrentcontext ();////draw a black (by default) vertical line,the Shaft of the arrow shaft//Cgcontextmovetopoint (con, +);//Cgcontextaddlinetopoint (con, +);//Cgconte Xtsetlinewidth (con);//Cgcontextstrokepath (con);////draw a red triangle,the point of the arrow//Cgcontextse Tfillcolorwithcolor (Con, [[Uicolor Redcolor] cgcolor]);//Cgcontextmovetopoint (con, +);//Cgcontextaddlinetopoi NT (con, 0);//Cgcontextaddlinetopoint (con, +);//Cgcontextfillpath (con);////snip a triangle out of th     e shaft by drawing in clear blend mode//cgcontextmovetopoint (Con, n, d);//Cgcontextmovetopoint (Con, 100, 90);// Cgcontextmovetopoint (Con, max),//Cgcontextsetblendmode (con, kcgblendmodeclear);//Cgcontextsetalpha (Con, 1     .0);//Cgcontextfillpath (con); When you need to obtain Cgpath, you can use uibezierpath//uibezierpath *p = [Uibezierpath bezierpath];////[P moveToPoint:Cgpointmake (+)];//[P addlinetopoint:cgpointmake (+)];//[P setlinewidth:20];//[P stroke];//[UI Color Redcolor] set];//[P removeallpoints];//[P Movetopoint:cgpointmake (+)];//[P ADDLINETOPOINT:CGPOINTMA Ke (0)];//[P addlinetopoint:cgpointmake (+)];//[P fill];////[P removeallpoints];//[P Movetopo    Int:cgpointmake (101)];//[P addlinetopoint:cgpointmake (+)];//[P Addlinetopoint:cgpointmake (110, 101)];//       [P fillwithblendmode:kcgblendmodeclear alpha:1.0];    Clipping cgcontextref con = uigraphicsgetcurrentcontext ();    Punch triangular hole in the context clipping region cgcontextmovetopoint (Con, 90, 100);    Cgcontextaddlinetopoint (Con, 100, 90);    Cgcontextaddlinetopoint (Con, 110, 100);    Cgcontextclosepath (con);    Cgcontextaddrect (Con, cgcontextgetclipboundingbox (con));    Cgcontexteoclip (con);    Draw the vertical line cgcontextmovetopoint (con, 100, 100); Cgcontextaddlinetopoint (CON, 100, 19);    Cgcontextsetlinewidth (Con, 20);    Cgcontextstrokepath (con);    Draw the red triangle.the point of the arrow cgcontextsetfillcolorwithcolor (Con, [[Uicolor Redcolor] cgcolor]);    Cgcontextmovetopoint (Con, 80, 25);    Cgcontextaddlinetopoint (Con, 100, 0);    Cgcontextaddlinetopoint (Con, 120, 25); Cgcontextfillpath (con);
Effect:









    Cgcontextref con = Uigraphicsgetcurrentcontext ();    [Self arrowimage] drawatpoint:cgpointmake (0, 0)];        for (int i=0; i<3; i++) {CGCONTEXTTRANSLATECTM (con, 20, 100);        Cgcontextrotatectm (Con, 30*m_pi/180);        Cgcontexttranslatectm (Con,-20,-100);            [Self arrowimage] drawatpoint:cgpointmake (0, 0)];    }//}-(UIImage *) arrowimage{uigraphicsbeginimagecontextwithoptions (Cgsizemake (+), NO, 0.0);    Cgcontextref con = Uigraphicsgetcurrentcontext ();    Punch triangular hole in the context clipping region cgcontextmovetopoint (Con, 10, 100);    Cgcontextaddlinetopoint (Con, 20, 90);    Cgcontextaddlinetopoint (Con, 30, 100);    Cgcontextclosepath (con);    Cgcontextaddrect (Con, cgcontextgetclipboundingbox (con));    Cgcontexteoclip (con);    Draw the vertical line cgcontextmovetopoint (con, 20, 100);    Cgcontextaddlinetopoint (Con, 20, 19);    Cgcontextsetlinewidth (Con, 20);    Cgcontextstrokepath (con); Draw the red triangle.the point ofThe arrow cgcontextsetfillcolorwithcolor (Con, [[Uicolor Redcolor] cgcolor]);    Cgcontextmovetopoint (Con, 0, 25);    Cgcontextaddlinetopoint (Con, 20, 0);    Cgcontextaddlinetopoint (Con, 40, 25);        Cgcontextfillpath (con);    UIImage *im = Uigraphicsgetimagefromcurrentimagecontext ();    Uigraphicsendimagecontext (); return im;}






When I'm not drawing in (0,0) There's a problem, as if it was caused by a coordinate system change.

    Cgcontextref con = Uigraphicsgetcurrentcontext ();    [Self arrowimage]  drawatpoint:cgpointmake ();    for (int i=0; i<12; i++) {        cgcontexttranslatectm (con, +);        Cgcontextrotatectm (Con, 30*m_pi/180);        Cgcontexttranslatectm (Con, -20, -100);        [Self arrowimage] drawatpoint:cgpointmake ();            }


Have not found the reason, have to know the children's shoes, welcome to inform, communicate together

Core Graphics Learning Note Image Drawing (ii)

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.