Signature drawing example on uiview.

 

The drawing software on the iPad is good. I bought a graffiti software from a child. Here is an example.

Canvas2d. h

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1. # Import <uikit/uikit. h>
2. # Import <quartzcore/quartzcore. h>
   
5. @ Interface canvas2d: uiview {
6. Nsmutablearray * arraystrokes;
7. Uicolor * currentcolor;
9. }
11. @ Property (retain) nsmutablearray * arraystrokes;
13. @ End

# Import <uikit/uikit. h> # import <quartzcore/quartzcore. h> @ interface canvas2d: uiview {nsmutablearray * arraystrokes; uicolor * currentcolor;} @ property (retain) nsmutablearray * arraystrokes; @ end

Canvas2d. m

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1. # Import "canvas2d. H"
4. @ Implementation canvas2d
6. @ Synthesize arraystrokes;
8. -(ID) initwithframe :( cgrect) Frame
9. {
10. Self = [Super initwithframe: frame];
11. If (Self ){
12. // Initialization code
13. Self. arraystrokes = [nsmutablearray array];
14. }
15. Return self;
16. }
18. -(ID) initwithcoder :( nscoder *) adecoder {
19. If (Self = [Super initwithcoder: adecoder]) {
20. Self. arraystrokes = [nsmutablearray array];
21. }
23. Return self;
24. }
27. // Only override drawrect: If you perform custom drawing.
28. // An empty implementation adversely affects performance during animation.
29. -(Void) drawrect :( cgrect) rect
30. {
31. // Drawing code
32. Cgcontextref context = uigraphicsgetcurrentcontext ();
34. Cgcontextsetlinewidth (context, 2.0 );
36. Cgcolorspaceref colorspace = cgcolorspacecreatedevicergb ();
38. Cgfloat components [] = {0.0, 0.0, 1.0, 1.0 };
39. Cgcolorref color = cgcolorcreate (colorspace, components );
41. Cgcontextsetstrokecolorwithcolor (context, color );
43. Cgcontextmovetopoint (context, 0, 0 );
44. Cgcontextaddlinetopoint (context, 300,400 );
46. Cgcontextstrokepath (context );
47. Cgcolorspacerelstrap (colorspace );
48. Cgcolorrelease (color );
50. If (self. arraystrokes)
51. {
52. Int arraynum = 0;
53. // Each iteration draw a stroke
54. // Line segments within a single stroke (PATH) has the same color and line width
55. For (nsdictionary * dictstroke in self. arraystrokes)
56. {
57. Nsarray * arraypointsinstroke = [dictstroke objectforkey: @ "points"];
58. Uicolor * color = [dictstroke objectforkey: @ "color"];
59. Float size = [[dictstroke objectforkey: @ "size"] floatvalue];
60. [Color set]; // equivalent to both setfill and setstroke
62. // Draw the stroke, line by line, with rounded Joints
63. Uibezierpath * pathlines = [uibezierpath bezierpath];
64. Cgpoint pointstart = cgpointfromstring ([arraypointsinstroke objectatindex: 0]);
65. [Pathlines movetopoint: pointstart];
66. For (INT I = 0; I <(arraypointsinstroke. Count-1); I ++)
67. {
68. Cgpoint pointnext = cgpointfromstring ([arraypointsinstroke objectatindex: I + 1]);
69. [Pathlines addlinetopoint: pointnext];
70. }
71. Pathlines. linewidth = size;
72. Pathlines. linejoinstyle = kcglinejoinround;
73. Pathlines. linecapstyle = kcglinecapround;
74. [Pathlines stroke];
76. Arraynum ++;
77. }
78. }
80. }
82. // Start new dictionary for each touch, with points and color
83. -(Void) touchesbegan :( nsset *) touches withevent :( uievent *) event
84. {
85. Nsmutablearray * arraypointsinstroke = [nsmutablearray array];
86. Nsmutabledictionary * dictstroke = [nsmutabledictionary dictionary];
87. [Dictstroke setobject: arraypointsinstroke forkey: @ "points"];
88. [Dictstroke setobject: [uicolor blackcolor] forkey: @ "color"];
89. [Dictstroke setobject: [nsnumber numberwithfloat: 5] forkey: @ "size"];
91. Cgpoint point = [[touches anyobject] locationinview: Self];
92. [Arraypointsinstroke addobject: nsstringfromcgpoint (point)];
94. [Self. arraystrokes addobject: dictstroke];
95. }
97. // Add each point to points Array
98. -(Void) touchesmoved :( nsset *) touches withevent :( uievent *) event
99. {
100. Cgpoint point = [[touches anyobject] locationinview: Self];
101. Cgpoint prevpoint = [[touches anyobject] previuslocationinview: Self];
102. Nsmutablearray * arraypointsinstroke = [[self. arraystrokes lastobject] objectforkey: @ "points"];
103. [Arraypointsinstroke addobject: nsstringfromcgpoint (point)];
105. Cgrect recttoredraw = cgrectmake (\
106. (Prevpoint. x> point. X )? Point. X: prevpoint. X)-5 ,\
107. (Prevpoint. Y> point. Y )? Point. Y: prevpoint. Y)-5 ,\
108. FABS (point. x-prevPoint.x) + 2*5 ,\
109. FABS (point. y-prevPoint.y) + 2*5 \
110. );
111. [Self setneedsdisplayinrect: recttoredraw];
112. }
114. // Send over new trace when the touch ends
115. -(Void) touchesended :( nsset *) touches withevent :( uievent *) event
116. {
117. }
121. -(Void) dealloc
122. {
123. [Arraystrokes release];
124. [Super dealloc];
125. }
127. @ End

# Import "canvas2d. H "@ implementation canvas2d @ synthesize arraystrokes;-(ID) initwithframe :( cgrect) frame {self = [Super initwithframe: frame]; If (Self) {// initialization codeself. arraystrokes = [nsmutablearray array];} return self;}-(ID) initwithcoder :( nscoder *) adecoder {If (Self = [Super initwithcoder: adecoder]) {self. arraystrokes = [nsmutablearray array];} return self;} // only override draw Rect: If you perform custom drawing. // an empty implementation adversely affects performance during animation. -(void) drawrect :( cgrect) rect {// drawing codecgcontextref context = uigraphicsgetcurrentcontext (); cgcontextsetlinewidth (context, 2.0); cgcolorspaceref colorspace = trim (); cgfloat components [] = {0.0, 0.0, 1.0, 1.0}; cgcolorref color = cgcolorcreate (colorspace, compone ETS); cgcontextsetstrokecolorwithcolor (context, color); cgcontextmovetopoint (context, 0, 0); cgcontextaddlinetopoint (context, 300,400); cgcontextstrokepath (context); cgcolorspacerel.pdf (colorspace ); cgcolorrelease (color); If (self. arraystrokes) {int arraynum = 0; // each iteration draw a stroke // line segments within a single stroke (PATH) has the same color and line widthfor (nsdictionary * dictstroke in Self. arraystrokes) {nsarray * arraypointsinstroke = [dictstroke objectforkey: @ "points"]; uicolor * color = [dictstroke objectforkey: @ "color"]; float size = [[dictstroke objectforkey: @ "size"] floatvalue]; [color set]; // equivalent to both setfill and setstroke // draw the stroke, line by line, with rounded jointsuibezierpath * pathlines = [uibezierpath bezierpath]; cgpoint pointstart = cgpointfromstring ([ar Raypointsinstroke objectatindex: 0]); [pathlines movetopoint: pointstart]; for (INT I = 0; I <(arraypointsinstroke. count-1); I ++) {cgpoint pointnext = cgpointfromstring ([arraypointsinstroke objectatindex: I + 1]); [pathlines addlinetopoint: pointnext];} pathlines. linewidth = size; pathlines. linejoinstyle = kcglinejoinround; pathlines. linecapstyle = kcglinecapround; [pathlines stroke]; arraynum ++ ;}}// start n EW dictionary for each touch, with points and color-(void) touchesbegan :( nsset *) touches withevent :( uievent *) event {nsmutablearray * arraypointsinstroke = [nsmutablearray array]; optional * dictstroke = [nsmutabledictionary dictionary]; [dictstroke setobject: arraypointsinstroke forkey: @ "points"]; [dictstroke setobject: [uicolor blackcolor] forkey: @ "color"]; [dictstroke setobject: [nsnumber n Umberwithfloat: 5] forkey: @ "size"]; cgpoint point = [[touches anyobject] locationinview: Self]; [arraypointsinstroke addobject: nsstringfromcgpoint (point)]; [self. arraystrokes addobject: dictstroke];} // Add each point to points array-(void) touchesmoved :( nsset *) touches withevent :( uievent *) event {cgpoint point = [[touches anyobject] locationinview: Self]; cgpoint prevpoint = [[touches anyobject] previou Slocationinview: Self]; nsmutablearray * arraypointsinstroke = [[self. arraystrokes lastobject] objectforkey: @ "points"]; [arraypointsinstroke addobject: nsstringfromcgpoint (point)]; cgrect recttoredraw = cgrectmake (\ (prevpoint. x> point. x )? Point. X: prevpoint. X)-5, \ (prevpoint. Y> point. Y )? Point. y: prevpoint. y)-5, \ FABS (point. x-prevPoint.x) + 2*5, \ FABS (point. y-prevPoint.y) + 2*5 \); [self setneedsdisplayinrect: recttoredraw];} // send over new trace when the touch ends-(void) touchesended :( nsset *) touches withevent :( uievent *) event {}-(void) dealloc {[arraystrokes release]; [Super dealloc];} @ end

Remember to add quartzcore. Framework

Usage: Associate view with canvas2d in XIB