基于MATLAB GUI的系统设计（二）

前面介绍了GUI及其创建步骤，从现在开始在对一些简单的实例进行实际操作，进一步熟悉GUI的创建步骤，本次先介绍两个实例。

实例一： 将一张彩色图像转化为黑白图像（彩色图像灰度化）。

第一步：GUIDE画界面。创建一个空的GUI界面，将需要的控件从左侧拖至右侧界面，并改变其属性。

第二步：编辑代码。在完成第一步后，点击“运行图窗”按钮，进入代码编辑界面。

function varargout=RGB2Gray(varargin)
% RGB2GRAY MATLAB code for RGB2Gray.fig
%      RGB2GRAY, by itself, creates a new RGB2GRAY or raises the existing
%      singleton*.
%
%      H = RGB2GRAY returns the handle to a new RGB2GRAY or the handle to
%      the existing singleton*.
%
%      RGB2GRAY('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in RGB2GRAY.M with the given input arguments.
%
%      RGB2GRAY('Property','Value',...) creates a new RGB2GRAY or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before RGB2Gray_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to RGB2Gray_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help RGB2Gray

% Last Modified by GUIDE v2.5 26-Jul-2019 14:11:52

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @RGB2Gray_OpeningFcn, ...
                   'gui_OutputFcn',  @RGB2Gray_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT

% --- Executes just before RGB2Gray is made visible.
function RGB2Gray_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to RGB2Gray (see VARARGIN)

% Choose default command line output for RGB2Gray
handles.output = hObject;
handles.imgfilename=[];
handles.imgdata=[];
handles.imgoutput=[];
% Update handles structure
guidata(hObject, handles);

% UIWAIT makes RGB2Gray wait for user response (see UIRESUME)
% uiwait(handles.figure1);

% --- Outputs from this function are returned to the command line.
function varargout = RGB2Gray_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;

% --- Executes on button press in open.
function open_Callback(hObject, eventdata, handles)
% hObject    handle to open (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
[imgfilename imgpathname]=uigetfile({'*.bmp;*.jpg;*.png;*.jpeg;*.tif;*.gif;*.Image files'},'载入图像');%打开图像 
if imgfilename
   imgdata=imread([imgpathname '\' imgfilename]);
   image(handles.axes1,imgdata); %在axes1中显示图像
   handles.imgfilename=imgfilename;
   handles.imgdata=imgdata;
end
guidata(hObject,handles)

% --- Executes on button press in RGB2Gray.
function RGB2Gray_Callback(hObject, eventdata, handles)
% hObject    handle to RGB2Gray (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if~isempty(handles.imgfilename)
    imgoutput=rgb2gray(handles.imgdata);
    image(handles.axes2,imgoutput)
    colormap(handles.axes2,gray(256))
    handles.imgoutput=imgoutput;
end

guidata(hObject,handles)

第三步：运行。在完成第一步和第二步后，点击MATLAB编辑器下面的“运行”按钮，会显示设计好的GUI界面。
第四步：在完成GUI界面创建后，对所创建界面的效果进行试验。先点击“Open RGB image"按钮选择一张彩色图像，再点击“RGB2Gray”按钮，就可以得到灰度图像。

实例二： 做一个录音机界面。

第一步：GUIDE画界面。

第二步：编辑代码。

function varargout = SoundRecorderDemo(varargin)
% SOUNDRECORDERDEMO MATLAB code for SoundRecorderDemo.fig
%      SOUNDRECORDERDEMO, by itself, creates a new SOUNDRECORDERDEMO or raises the existing
%      singleton*.
%
%      H = SOUNDRECORDERDEMO returns the handle to a new SOUNDRECORDERDEMO or the handle to
%      the existing singleton*.
%
%      SOUNDRECORDERDEMO('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in SOUNDRECORDERDEMO.M with the given input arguments.
%
%      SOUNDRECORDERDEMO('Property','Value',...) creates a new SOUNDRECORDERDEMO or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before SoundRecorderDemo_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to SoundRecorderDemo_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help SoundRecorderDemo

% Last Modified by GUIDE v2.5 26-Jul-2019 15:02:18

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @SoundRecorderDemo_OpeningFcn, ...
                   'gui_OutputFcn',  @SoundRecorderDemo_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT

% --- Executes just before SoundRecorderDemo is made visible.
function SoundRecorderDemo_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to SoundRecorderDemo (see VARARGIN)

% Choose default command line output for SoundRecorderDemo
handles.output = hObject;
handles.recObj = audiorecorder(48000,16,2,-1);
handles.recObj.TimerFcn={@RecDisplay,handles};
handles.recObj.TimerPeriod=0.25;
handles.playSpeed=1;
% Update handles structure
guidata(hObject, handles);

% UIWAIT makes SoundRecorderDemo wait for user response (see UIRESUME)
% uiwait(handles.figure1);

% --- Outputs from this function are returned to the command line.
function varargout = SoundRecorderDemo_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;

% --- Executes on button press in statt.
function statt_Callback(hObject, eventdata, handles)
% hObject    handle to statt (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
record(handles.recObj);

% --- Executes on button press in stop.
function stop_Callback(hObject, eventdata, handles)
% hObject    handle to stop (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
stop(handles.recObj)

% --- Executes on button press in play.
function play_Callback(hObject, eventdata, handles)
% hObject    handle to play (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
handles.myRecording=getaudiodata(handles.recObj);
handles.playObj=audioplayer(handles.myRecording,handles.playSpeed*handles.recObj.SampleRate);
play(handles.playObj);
guidata(hObject,handles);

% --- Executes on button press in save.
function save_Callback(hObject, eventdata, handles)
% hObject    handle to save (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
[file,path]=uiputfile(['soundDemo_Speed' num2str(handles.playSpeed) '.wav'],'Save recorded sound');
if file
    audiowrite([path '\' file],handles.myRecording,handles.playSpeed*handles.recObj.SampleRate)
end

function RecDisplay(hObject, eventdata, handles)
% handles
handles.myRecording=getaudiodata(handles.recObj)
% axes(handles.axes1)
plot(handles.axes1,(1:length(handles.myRecording))/handles.recObj.SampleRate,handles.myRecording)
drawnow;

function edit1_Callback(hObject, eventdata, handles)
% hObject    handle to edit1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit1 as text
%        str2double(get(hObject,'String')) returns contents of edit1 as a double
handles.playSpeed=str2double(get(hObject,'String'));
guidata(hObject,handles)

% --- Executes during object creation, after setting all properties.
function edit1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

第三步：运行。

第四步：在完成GUI界面创建后，对所创建界面的效果进行试验。点击“Start”按钮开始录音，点击“Stop”按钮暂停录音，点击“Play”按钮开始播放刚录好的音频，点击“Save”按钮可以将刚录好的音频保存到指定路径。在播放音频时，可以修改可编辑文本框中的播放速度，比如改为“1.5”或“0.75”。