Canvas_2D class
This is a sub-class of the Canvas class, to deal especifically with axes that present only 2D behavior.
Contents
Authors
- Pedro Cortez F Lopes (pedrocortez@id.uff.br)
- Rafael Lopez Rangel (rafaelrangel@tecgraf.puc-rio.br)
- Luiz Fernando Martha (lfm@tecgraf.puc-rio.br)
History
@version 1.00
Initial version: September 2020
Initially prepared for the course CIV 2801 - Fundamentos de Computação Gráfica, 2020, second term, Department of Civil Engineering, PUC-Rio.
Class definition
classdef Canvas_2D < Canvas
Constructor method
methods
function this = Canvas_2D(ax,fig,fcn)
if (nargin == 0)
ax = [];
fig = [];
fcn = [];
elseif (nargin <= 2)
fcn = [];
end
this = this@Canvas(ax,fig,fcn);
end
end
Public methods
Implementation of the abstract methods declared in super-class Canvas.
methods
%------------------------------------------------------------------
% Fits axis limits to display everything drawn on canvas
function fit2view(this,bBox)
% Set axes units to pixels
dfltUnits = get(this.ax, 'Units');
set(this.ax, 'Units', 'pixels');
% Compute canvas height/width ratio
h_w = this.ax.Position(4)/this.ax.Position(3);
% Set axes units back to what they were
set(this.ax, 'Units', dfltUnits);
% Check if a bounding box was already provided
if (nargin == 2)
if ~isempty(bBox)
% Get x and y vectors
x = [bBox(1),bBox(3)];
xmin = min(x);
xmax = max(x);
y = [bBox(2),bBox(4)];
ymin = min(y);
ymax = max(y);
% Compute window sizes based on model bounding box size
% increased by current free border factor.
% Place window center at model bounding box center pos.
%%%%% COMPLETE HERE - CANVAS_2D: 01 %%%%%
Lx = (xmax - xmin) * (1.0 + this.freeBorder);
Mx = (xmax + xmin) * 0.5;
Ly = (ymax - ymin) * (1.0 + this.freeBorder);
My = (ymax + ymin) * 0.5;
%%%%% COMPLETE HERE - CANVAS_2D: 01 %%%%%
y_x = Ly / Lx;
% If axIsEq, make sure bound box fits while respecting
% proportional limits
if this.axIsEq
%%%%% COMPLETE HERE - CANVAS_2D: 02 %%%%%
if y_x > h_w
Lx = Ly / h_w;
else
Ly = Lx * h_w;
end
%%%%% COMPLETE HERE - CANVAS_2D: 02 %%%%%
end
% Set limits and return
%%%%% COMPLETE HERE - CANVAS_2D: 03 %%%%%
xmin = Mx - (Lx * 0.5);
xmax = Mx + (Lx * 0.5);
ymin = My - (Ly * 0.5);
ymax = My + (Ly * 0.5);
%%%%% COMPLETE HERE - CANVAS_2D: 03 %%%%%
this.ax.XLim = [xmin,xmax];
this.ax.YLim = [ymin,ymax];
% Set flag to indicate that bounding box was provided
this.bBoxWasSet = true;
return;
end
end
% Get list of handles to graphic objects drawn on this.ax
plots = this.ax.Children;
% If there is nothing drawn on this.ax, return
if isempty(plots)
if ~this.axIsEq
this.ax.XLim = [-5,5];
this.ax.YLim = [-5,5];
elseif h_w > 1
this.ax.XLim = [-5,5];
this.ax.YLim = [-5*h_w,5*h_w];
else
this.ax.XLim = [-5/h_w,5/h_w];
this.ax.YLim = [-5,5];
end
return
end
% Get maximum and minimum coordinates
if ~strcmp(plots(1).Type,'text')
xmax = max(plots(1).XData);
xmin = min(plots(1).XData);
ymax = max(plots(1).YData);
ymin = min(plots(1).YData);
else
xmax = max(plots(1).Position(1));
xmin = min(plots(1).Position(1));
ymax = max(plots(1).Position(2));
ymin = min(plots(1).Position(2));
end
for i = 2:length(plots)
if ~strcmp(plots(i).Type,'text')
xmax = max([xmax,max(plots(i).XData)]);
xmin = min([xmin,min(plots(i).XData)]);
ymax = max([ymax,max(plots(i).YData)]);
ymin = min([ymin,min(plots(i).YData)]);
else
xmax = max([xmax,max(plots(i).Position(1))]);
xmin = min([xmin,min(plots(i).Position(1))]);
ymax = max([ymax,max(plots(i).Position(2))]);
ymin = min([ymin,min(plots(i).Position(2))]);
end
end
% Compute window sizes based on model bounding box size
% increased by current free border factor.
% Place window center at model bounding box center position
%%%%% COMPLETE HERE - CANVAS_2D: 01 (REPEAT CANVAS_2D: 01 ABOVE %%%%%
Lx = (xmax - xmin) * (1.0 + this.freeBorder);
Mx = (xmax + xmin) * 0.5;
Ly = (ymax - ymin) * (1.0 + this.freeBorder);
My = (ymax + ymin) * 0.5;
%%%%% COMPLETE HERE - CANVAS_2D: 01 (REPEAT CANVAS_2D: 01 ABOVE %%%%%
y_x = Ly/Lx;
% Adjust window limits such that window rectangle has same
% aspect ratio of viewport rectangle
if this.axIsEq
%%%%% COMPLETE HERE - CANVAS_2D: 02 (REPEAT CANVAS_2D: 02 ABOVE) %%%%%
if y_x > h_w
Lx = Ly / h_w;
else
Ly = Lx * h_w;
end
%%%%% COMPLETE HERE - CANVAS_2D: 02 (REPEAT CANVAS_2D: 02 ABOVE) %%%%%
end
% Compute adjusted window limits
%%%%% COMPLETE HERE - CANVAS_2D: 03 (REPEAT CANVAS_2D: 03 ABOVE) %%%%%
xmin = Mx - (Lx * 0.5);
xmax = Mx + (Lx * 0.5);
ymin = My - (Ly * 0.5);
ymax = My + (Ly * 0.5);
%%%%% COMPLETE HERE - CANVAS_2D: 03 (REPEAT CANVAS_2D: 03 ABOVE) %%%%%
this.ax.XLim = [xmin,xmax];
this.ax.YLim = [ymin,ymax];
% Set flag to indicate that bounding box was provided
this.bBoxWasSet = true;
end
%------------------------------------------------------------------
% Mouse button down callback - related to axes object
% Input:
% * this = handle to this canvas object
% * obj = handle to axes associated to canvas
% * event = struct with event data
function ax_onButtonDown(~,~,~)
end
%------------------------------------------------------------------
% Mouse button down callback - generic callback, called from an
% Emouse object.
% Input:
% * this = handle to this canvas object
% * pt = current cursor coordinates
% * whichMouseButton = 'left', 'right', 'center', 'double click'
function onButtonDown(~,~,~)
end
%------------------------------------------------------------------
% Mouse button up callback - generic callback, called from an
% Emouse object.
% Input:
% * this = handle to this canvas object
% * pt = current cursor coordinates
% * whichMouseButton = 'left', 'right', 'center', 'double click'
function onButtonUp(~,~,~)
end
%------------------------------------------------------------------
% Mouse move callback - generic callback, called from an
% Emouse object.
% Input:
% * this = handle to this canvas object
% * pt = current cursor coordinates
function onMouseMove(~,~)
end
%------------------------------------------------------------------
% Mouse scroll callback - generic callback, called from an
% Emouse object.
% Input:
% * this = handle to this canvas object
% * pt = current cursor coordinates
function onMouseScroll(~,~)
end
end
end