Introduction to M ATLAB Basic Graphics

Copyright  by The MathWorks, Inc. Basic Graphics - 2 Introduction to M ATLAB Section Outline 2-D plotting Graph Annotation Subplots & Alternative Axes 3-D plotting Specialized plotting routines Patches & Images Saving & Exporting Figures Introduction to Handle Graphics Ref: Color, Linestyle, Marker options Special characters using LaTeX

Copyright  by The MathWorks, Inc. Basic Graphics - 3 Introduction to M ATLAB 2-D Plotting Specify x-data and/or y-data Specify color, line style and marker symbol (Default values used if ‘clmnot specified) Syntax: Plotting single line: Plotting multiple lines: plot(x1, y1, 'clm1', x2, y2, 'clm2',...) plot(xdata, ydata, 'color_linestyle_marker') Ref: Color, Linestyle, Marker options

Copyright  by The MathWorks, Inc. Basic Graphics - 4 Introduction to M ATLAB 2-D Plotting - example Create a Blue Sine Wave » x = 0:.1:2*pi; » y = sin(x); » plot(x,y) » x = 0:.1:2*pi; » y = sin(x); » plot(x,y) »plot_2d

Copyright  by The MathWorks, Inc. Basic Graphics - 5 Introduction to M ATLAB Adding a Grid GRID ON creates a grid on the current figure GRID OFF turns off the grid from the current figure GRID toggles the grid state »grid on

Copyright  by The MathWorks, Inc. Basic Graphics - 6 Introduction to M ATLAB Adding additional plots to a figure HOLD ON holds the current plot HOLD OFF releases hold on current plot HOLD toggles the hold state »addgraph » x = 0:.1:2*pi; » y = sin(x); » plot(x,y,'b') » grid on » hold on » plot(x,exp(-x),'r:*') » x = 0:.1:2*pi; » y = sin(x); » plot(x,y,'b') » grid on » hold on » plot(x,exp(-x),'r:*')

Copyright  by The MathWorks, Inc. Basic Graphics - 7 Introduction to M ATLAB Controlling viewing area ZOOM ON allows user to select viewing area ZOOM OFF prevents zooming operations ZOOM toggles the zoom state AXIS sets axis range [xmin xmax ymin ymax] » axis([0 2*pi 0 1])

Copyright  by The MathWorks, Inc. Basic Graphics - 8 Introduction to M ATLAB Graph Annotation TITLE TEXT or GTEXT XLABEL YLABEL »annotation LEGEND

Copyright  by The MathWorks, Inc. Basic Graphics - 9 Introduction to M ATLAB Plot Editor »plotedit Right click (Ctrl-LFT): on graphics objects to modify properties Enable Plotting Editing Add Text Add Arrow Add Line Zoom In Zoom Out Rotate 3D [Edit] -> Copy Figure / Options

Copyright  by The MathWorks, Inc. Basic Graphics - 10 Introduction to M ATLAB Using LaTeX in Graph Annotations Font Type (applies inside {} or until changed): \fontname{ } AND \fontsize{ } Appearance (applies inside {} or until removed): \bf boldface \it OR \slitalics OR slanted \rmremove text formatting (normal) Subscript “_” or superscript “^”: Applies to next character or {text in curly braces} Greek letters and Symbols (prefix with “\”): Selected symbols, e.g. '\pi' =  »latex_examp Ref: Special characters using LaTeX

Copyright  by The MathWorks, Inc. Basic Graphics - 11 Introduction to M ATLAB Exercise: 2-D Plotting Create the following graph: fontsize (14) sin(10  t) cos(10  t) Courier New + Bold

Copyright  by The MathWorks, Inc. Basic Graphics - 12 Introduction to M ATLAB Solution: 2-D Plotting » t = 0:0.01:0.5; » plot(t,sin(10*pi*t),'g-*',... t,cos(10*pi*t),'k:o') » title(['\fontsize{14}In-Phase ({\itsolid})',... 'and Quadrature ({\itdotted}) Signals']) » xlabel('\fontname{Courier New}\bfTime (\mus)') » ylabel('{\it''Normalized''} Signals'); » text(0.2, cos(2*pi)+0.1, '\leftarrow----\rightarrow'); » text(0.175, cos(2*pi)+0.2, '^\pi/_2 phase lag'); » axis([ ]); % NOTE: Could have also used GTEXT or PLOTEDIT: % ============================================= % gtext('\leftarrow----\rightarrow'); % gtext('^\pi/_2 phase lag'); » t = 0:0.01:0.5; » plot(t,sin(10*pi*t),'g-*',... t,cos(10*pi*t),'k:o') » title(['\fontsize{14}In-Phase ({\itsolid})',... 'and Quadrature ({\itdotted}) Signals']) » xlabel('\fontname{Courier New}\bfTime (\mus)') » ylabel('{\it''Normalized''} Signals'); » text(0.2, cos(2*pi)+0.1, '\leftarrow----\rightarrow'); » text(0.175, cos(2*pi)+0.2, '^\pi/_2 phase lag'); » axis([ ]); % NOTE: Could have also used GTEXT or PLOTEDIT: % ============================================= % gtext('\leftarrow----\rightarrow'); % gtext('^\pi/_2 phase lag'); »plot2d_soln

Copyright  by The MathWorks, Inc. Basic Graphics - 13 Introduction to M ATLAB Subplots SUBPLOT- display multiple axes in the same figure window » subplot(2,2,1); » plot(1:10) » subplot(2,2,2) » x = 0:.1:2*pi; » plot(x,sin(x)) » subplot(2,2,3) » x = 0:.1:2*pi; » plot(x,exp(-x),’r’) » subplot(2,2,4) » plot(peaks) » subplot(2,2,1); » plot(1:10) » subplot(2,2,2) » x = 0:.1:2*pi; » plot(x,sin(x)) » subplot(2,2,3) » x = 0:.1:2*pi; » plot(x,exp(-x),’r’) » subplot(2,2,4) » plot(peaks) »subplotex subplot(#rows, #cols, index)

Copyright  by The MathWorks, Inc. Basic Graphics - 14 Introduction to M ATLAB Alternative Scales for Axes SEMILOGY log Y linear X PLOTYY 2 sets of linear axes LOGLOG Both axes logarithmic SEMILOGX log X linear Y »other_axes

Copyright  by The MathWorks, Inc. Basic Graphics - 15 Introduction to M ATLAB 3-D Line Plotting Ref: Color, Linestyle, Marker options » z = 0:0.1:40; » x = cos(z); » y = sin(z); » plot3(x,y,z) » z = 0:0.1:40; » x = cos(z); » y = sin(z); » plot3(x,y,z) plot3(xdata, ydata, zdata, 'clm',...) »plot_3d

Copyright  by The MathWorks, Inc. Basic Graphics - 16 Introduction to M ATLAB 3-D Surface Plotting »surf_3d

Copyright  by The MathWorks, Inc. Basic Graphics - 17 Introduction to M ATLAB Exercise: 3-D Plotting Data from a water jet experiment suggests the following non-linear model for the 2-D stress in the cantilever beam’s horizontal plane. where:  = localized planar stress [MPa] x = distance from end of beam [10 -1 m] y = distance from centerline of beam [10 -1 m] For the particular setup used: (x = {0 to 6}, y = {-3 to 3},  =  =  = 1,  = - 0.2) Plot the resulting stress distribution  =  e -  x [sin(  x)*cos(  y)] x

Copyright  by The MathWorks, Inc. Basic Graphics - 18 Introduction to M ATLAB Solution: 3-D Plotting » B = -0.2; » x = 0:0.1:2*pi; » y = -pi/2:0.1:pi/2; » [x,y] = meshgrid(x,y); » z = exp(B*x).*sin(x).*cos(y); » surf(x,y,z) » B = -0.2; » x = 0:0.1:2*pi; » y = -pi/2:0.1:pi/2; » [x,y] = meshgrid(x,y); » z = exp(B*x).*sin(x).*cos(y); » surf(x,y,z) »plot3d_soln

Copyright  by The MathWorks, Inc. Basic Graphics - 19 Introduction to M ATLAB Specialized Plotting Routines »spec_plots

Copyright  by The MathWorks, Inc. Basic Graphics - 20 Introduction to M ATLAB Specialized Plotting Routines (2) »spec_plots2

Copyright  by The MathWorks, Inc. Basic Graphics - 21 Introduction to M ATLAB » a = magic(4) a = » image(a); » map = hsv(16) map = » colormap(map) » a = magic(4) a = » image(a); » map = hsv(16) map = » colormap(map) Images Reduced Memory Requirements: Images represented as UINT8 - 1 byte »imagex Use Row 2 of colormap for pixel (1,2) Row 2

Copyright  by The MathWorks, Inc. Basic Graphics - 22 Introduction to M ATLAB Example: Images » load cape » image(X) » colormap(map) » load cape » image(X) » colormap(map)

Copyright  by The MathWorks, Inc. Basic Graphics - 23 Introduction to M ATLAB Saving Figures 2 files created:.m- text file.mat- binary data file. »plot3d_soln

Copyright  by The MathWorks, Inc. Basic Graphics - 24 Introduction to M ATLAB using the Dialog Box: File Menu / Print... >>printdlg from Command Line: (Switches are optional) Controlling Page Layout: File Menu / Page Position >>pagedlg Printing Figures print -devicetype -options

Copyright  by The MathWorks, Inc. Basic Graphics - 25 Introduction to M ATLAB Printing image to a file: Print Dialog Box: (File / Print...) >>printdlg Command Line: (Switches are optional) Copying to Clipboard: Options:(File / Preferences) Copying:(Edit / Copy Figure) Exporting Figures print -devicetype -options filename

Copyright  by The MathWorks, Inc. Basic Graphics - 26 Introduction to M ATLAB Introduction to Handle Graphics Graphics in MATLAB consist of objects Every graphics objects has a unique handle and a set of properties which define it’s appearance. Objects are arranged in terms of a set hierarchy

Copyright  by The MathWorks, Inc. Basic Graphics - 27 Introduction to M ATLAB Hierarchy of Graphics Objects Root object Figure object UIControl objects UIMenu objects Axes object Figure object Surface object Line objects Text objects UIControl objects UIMenu objects Axes object Figure object

Copyright  by The MathWorks, Inc. Basic Graphics - 28 Introduction to M ATLAB 1. Upon Creation 2. Utility Functions 0- root object handle gcf- current figure handle gca- current axis handle gco- current object handle 3. FINDOBJ Obtaining an Object’s Handle h_obj = findobj(h_parent, 'Property', 'Value',...) h_line = plot(x_data, y_data,...) What is the current object? Last object created OR Last object clicked Default = 0 (root object)

Copyright  by The MathWorks, Inc. Basic Graphics - 29 Introduction to M ATLAB Deleting Objects - DELETE » h = findobj('Color', [0 0 1]) » delete(h) » h = findobj('Color', [0 0 1]) » delete(h) delete(h_object) » addgraph

Copyright  by The MathWorks, Inc. Basic Graphics - 30 Introduction to M ATLAB Modifying Object Properties Using GET & SET Obtaining a list of current properties: Obtaining a list of settable properties: Modifying an object’s properties: get(h_object) set(h_object) set(h_object, 'PropertyName', 'New_Value',...) Ref: HELPDESK - Handle Graphics Objects: \help\techdoc\infotool\hgprop\doc_frame.html

Copyright  by The MathWorks, Inc. Basic Graphics - 31 Introduction to M ATLAB Modifying Object Properties Using the Property Editor Property List: List of properties & current values for selected object »propedit Object Browser: Hierarchical list of graphics objects Property / Value Fields: Selected property & current value (modify here)

Copyright  by The MathWorks, Inc. Basic Graphics - 32 Introduction to M ATLAB Modifying Object Properties Using the RIGHT CLICK

Copyright  by The MathWorks, Inc. Basic Graphics - 33 Introduction to M ATLAB Working with Defaults - setting Most properties have pre-defined 'factory' values (Used whenever property values are not specified.) You can define your own 'default' values to be used for creating new objects. (Put default settings in “startup.m” to apply to whole session) Syntax: set(ancestor,'Default ', ) Use root object (0) to apply to all new objects

Copyright  by The MathWorks, Inc. Basic Graphics - 34 Introduction to M ATLAB » set(0, 'DefaultSurfaceEdgeColor', 'b') » h=surf(peaks(15)); » set(0, 'DefaultSurfaceEdgeColor', 'b') » h=surf(peaks(15)); Set the Default Surface EdgeColor to Blue & create new surface. » set(h, 'EdgeColor', 'g') Green Set the EdgeColor to Green » set(h, 'EdgeColor', 'default') specifies Default value Reset back to Default Value » set(h, 'EdgeColor', 'factory') specifies Factory value Reset back to Factory Value Example: Working with Defaults »defaults

Copyright  by The MathWorks, Inc. Basic Graphics - 35 Introduction to M ATLAB Return Default Property Value to Factory Setting: Create a new surface: Working with Defaults - removing » set(gcf, 'DefaultSurfaceEdgeColor', 'factory') » set(gcf, 'DefaultSurfaceEdgeColor', 'remove') » h = surf(peaks(15)); »defaults OR