iOS drawing, drawing coordinate system, drawing coordinate system

Let's take a look at the effect:

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creates a new view class. To add code directly:

Only override Drawrect:if-perform custom drawing.//an empty implementation adversely affects performance during a        nimation.-(void) DrawRect: (cgrect) rect{//Get current environment cgcontextref context = Uigraphicsgetcurrentcontext ();        Save the current environment to facilitate later recovery of cgcontextsavegstate (context);         Organize the data for (int i = 0; i < Self.dataArray.count; i++) {NSString * x_data = self.dataarray[i][@ "xxx"];        NSString * y_data = self.dataarray[i][@ "yyyy"];                NSString * rate_data = self.dataarray[i][@ "RRR"];        [X_array Addobject:x_data];        [Y_array Addobject:y_data];    [Rate_array Addobject:rate_data];    }//Rectangular drawing area cgrect Rectangle = rect;    Defines a rectangular path uibezierpath *path = [Uibezierpath bezierpathwithrect:rectangle];        Draw the rectangle path [path stroke];                    Public data float fdistance_left_frame = 30.0; The width of the left side x-axis distance border. Float Fdistance_botto for drawing textM_frame = 15.0;                   Left side y-axis distance border Width float fdistance_right_frame = 10.0;  Left x axis distance border width float fdraw_line_height = rect.size.height-fdistance_bottom_frame; Height of drawing coordinates float fdraw_line_width = Rect.size.width-fdistance_left_frame-fdistance_r  Ight_frame;                    Draw the width of the coordinate float f_x_axis_scale_number = 7.0;                    X-Axis Large tick count float f_y_axis_scale_number = 7.0;                    Y-axis number of ticks float x_unit_distance_scale = 0.0;                    Offset of the x-axis scale float Y_unit_distance_scale = 0.0;                             Offset of the y-axis scale float X_unit_scale = 0.0;                             The span of the x-axis scale (a proportional unit) float Y_unit_scale = 0.0;    The span of the y-axis scale (a proportional unit)//start drawing x-axis Float left_bottom_x = rect.origin.x + fdistance_left_frame;    Float left_bottom_y = rect.origin.y + fdraw_line_height;              Cgpoint Point_origin = Cgpointmake (left_bottom_x, left_bottom_y); Axis Origin//define a start path Uibezierpath * X_startpath = [Uibezierpath Bezierpath];        [X_startpath setlinewidth:1.5];                                        [X_startpath Movetopoint:point_origin]; Set start point (coordinate origin) for (int x = 0; x < F_x_axis_scale_number; + +)//Draw straight line {X_un                    It_scale = Fdraw_line_height/f_x_axis_scale_number;                                  One-level division large scale X_unit_distance_scale = x * X_unit_scale;                The offset point of the relative Origin [X_startpath addlinetopoint:cgpointmake (left_bottom_x, Left_bottom_y-x_unit_distance_scale)]; |        The left side of the x-axis draws text float text_height_certer = left_bottom_y;        float text_rect_top = text_height_certer-8-X_unit_distance_scale;    Float Text_rect_bottom = text_height_certer + 8-x_unit_distance_scale; +8-8.        Give the text a height of 16 pixels float text_rect_height = 16;             CGRect x_axis_rect = CGRectMake (2, Text_rect_top, Fdistance_left_frame, text_rect_height);   Cgcontextsetlinewidth (context, 1.0);        Cgcontextsetrgbfillcolor (context, 0.5, 0.5, 0.5, 0.5);                         Uifont *font = [Uifont boldsystemfontofsize:12.0];             Font with 12th number NSString * X_strtext = [NSString stringwithformat:@ "%zi.00", X];                Draw x-axis scale values [X_strtext drawinrect:x_axis_rect Withfont:font]; if (0 = = x) {//IS ' 0 '. No or that draws the scale.            Draw the horizontal line "Y" axis float y_width = Fdraw_line_width directly at the bottom; Cgcontextsetrgbstrokecolor (context, 0.5, 0.5, 0.5, 0.5);//Line Color Cgcontextmovetopoint (context, left_bottom_x, lef            T_bottom_y-x_unit_distance_scale);            Cgcontextaddlinetopoint (context, left_bottom_x + y_width, Left_bottom_y-x_unit_distance_scale);                        Cgcontextstrokepath (context);            Start drawing y-Axis Uibezierpath * Y_startpath = [Uibezierpath Bezierpath];            [Y_startpath setlinewidth:1.5];                 [Y_startpath Movetopoint:point_origin]; The starting point of the y-axis is alsois the x-axis tick start point for (int y = 0; y < F_y_axis_scale_number + 1; y++)//Draw straight line {               Y_unit_scale = Fdraw_line_width/f_y_axis_scale_number;                            One-level division large scale Y_unit_distance_scale = y * y_unit_scale;                                 The offset point of the relative Origin [Y_startpath addlinetopoint:cgpointmake (left_bottom_x, Left_bottom_y-x_unit_distance_scale)];                "-" Y-axis lower drawing text float y_text_left_certer = left_bottom_x;                Float Y_text_rect_left = y_text_left_certer-15 + Y_unit_distance_scale;                Float Y_text_rect_top = left_bottom_y + 2;                Float Y_text_rect_width = y_text_left_certer + + Y_unit_distance_scale;                                +10-10, gives the text 20 pixels width of float y_text_rect_height = 16;               CGRect y_axis_rect = CGRectMake (Y_text_rect_left, Y_text_rect_top, Y_text_rect_width, y_text_rect_height);                 Cgcontextsetlinewidth (context, 1.5);                Line width cgcontextsetrgbfillcolor (context, 0.5, 0.5, 0.5, 0.5);              Uifont *font = [Uifont boldsystemfontofsize:12.0];                                Font with 12th number//NSString * Y_strtext = [NSString stringwithformat:@ "%zi.00", y];//draw y-axis scale values                NSString * Y_strtext = [Y_array objectatindex:f_y_axis_scale_number-y];                    Y_strtext = [Y_strtext substringfromindex:5];                                Draw y-axis scale values [Y_strtext drawinrect:y_axis_rect Withfont:font]; if (y = = 0) {} else {//"-" Y-axis Upper draw scale short line float FSCA                    Le_width = 5.0;      Cgcontextsetrgbstrokecolor (context, 0.5, 0.5, 0.5, 0.5);                    Line Color Cgcontextmovetopoint (context, left_bottom_x + Y_unit_distance_scale, left_bottom_y); CgcontextaddlineTopoint (context, left_bottom_x + Y_unit_distance_scale, left_bottom_y-fscale_width);                Cgcontextstrokepath (context);   }} [Y_startpath stroke]; Draws line based on coordinate point} else {//"|"            The x-axis draws the right-hand scale short float fscale_width = 5.0; Cgcontextsetrgbstrokecolor (context, 0.5, 0.5, 0.5, 0.5);//Line Color Cgcontextmovetopoint (context, left_bottom_x, le            Ft_bottom_y-x_unit_distance_scale);            Cgcontextaddlinetopoint (context, left_bottom_x + fscale_width, Left_bottom_y-x_unit_distance_scale);        Cgcontextstrokepath (context); }////Draw level two small scale value//for (int xx = 0; xx < 5; xx++)//{//float fsmall_scale_width = 3.0;/ /Cgcontextsetrgbstrokecolor (context, 0.5, 0.5, 0.5, 0.5);//Line Color//cgcontextsetlinewidth (context, 1                    .0); Line width//float fsmall_scale_height = x_unit_distance_scale/10.0; The height of each small scaleInvariant//Cgcontextmovetopoint (context, point_origin.x, point_origin.y-fsmall_scale_height);//Cgcontex Taddlinetopoint (context, point_origin.x + fsmall_scale_width, point_origin.y-fsmall_scale_height);//CGContex   Tstrokepath (context);//}} [X_startpath stroke];    Draws line according to the coordinate point connection [[Uicolor Bluecolor] setfill];            [X_startpath fill]; // "|" The x-axis draws a dashed line.    Horizontal dashed cgfloat dasharray[] = {2.0, 2.0};    Cgcontextsetlinedash (context, 0, Dasharray, 2);    Cgcontextsetrgbstrokecolor (context,0.5, 0.5, 0.5, 0.5);//Line color for (int x = 1; x < F_x_axis_scale_number + 1; + +)        Draw a dashed line {X_unit_distance_scale = x * (X_unit_scale);        One-level division large scale Cgcontextmovetopoint (context, left_bottom_x + 5, Left_bottom_y-x_unit_distance_scale);    Cgcontextaddlinetopoint (context, left_bottom_x + fdraw_line_width, Left_bottom_y-x_unit_distance_scale); } for (int y = 1; y < F_y_axis_scale_number + 1; y++)//Draw dashed line   {Y_unit_distance_scale = y * (y_unit_scale);        One-level division large scale Cgcontextmovetopoint (context, point_origin.x + Y_unit_distance_scale, point_origin.y-5); Cgcontextaddlinetopoint (context, point_origin.x + Y_unit_distance_scale, Point_origin.y-fdraw_line_height +    Fdistance_bottom_frame + 3);           } cgcontextstrokepath (context);            Start drawing the graph Cgcontextsetlinedash (context, 0.0,null, 0);                    Restore Brush Cgcontextsetlinewidth (context,1.0);   Set to Solid line brush Cgcontextsetrgbstrokecolor (context, 1.0, 0, 0, 0.5); Line color for (int a = 0; a < X_array.count; a++) {//y-axis date backwards traversal, here data also backwards traverse float fdata = [[X_array obj        Ectatindex:x_array.count-1-A] floatvalue];                                 Cgpoint data_point = cgpointmake (point_origin.x + A * y_unit_scale, point_origin.y-fdata * x_unit_scale); Axis Origin if (0 = = a) {Cgcontextmovetopoint (context, Data_point.x, Data_point.        y); }        else {cgcontextaddlinetopoint (context, data_point.x, DATA_POINT.Y);            } NSLog (@ "%zi = = (%f,%f)", A, data_point.x, DATA_POINT.Y);        } cgcontextstrokepath (context); Start Border dot Cgcontextsetrgbstrokecolor (context, 1.0, 0.0, 0.0, 1.0);//Brush Line Color cgcontextsetlinewidth (context, 2.0);//width of line Degrees//void Cgcontextaddarc (cgcontextref c,cgfloat x, cgfloat y,cgfloat radius,cgfloat startangle,cgfloat endAngle, int cl ockwise) 1 radians =180°/π (≈57.3°) degrees = radians x180°/π360°=360xπ/180 =2π radians//x, y for dot coordinates, radius radius, startangle for start radians, endangle for end radians, cl        Ockwise 0 is clockwise and 1 is counterclockwise.  for (int a = 0; a < X_array.count; a++) {//y-axis date backwards traversal, here the data is also backwards traversing float fdata = [[X_array objectatindex:        X_array.count-1-A] floatvalue];                                 Cgpoint data_point = cgpointmake (point_origin.x + A * y_unit_scale, point_origin.y-fdata * x_unit_scale); Axis Origin Cgcontextaddarc (context, Data_point.x, Data_point.y, 1, 0, 2 * PI, 0); Join a circle} cgcontextdrawpath (context, kcgpathstroke); Draw path}bible 2015-07-15 17:24:10//file header Add macro definition # define PI 3.1415926

Source code Download: http://download.csdn.net/detail/bible521125/8902893

C + + to iOS soon used a bit of a mess, such as need to be able to organize themselves.

iOS drawing, drawing coordinate system, drawing coordinate system