Matlab: Videowriter创建只有部分图形的视频。

Question

我制作了一个剧本，描绘了火卫一、MEX和MAVEN环绕火星的轨道的动画。我想要这个动画的视频。它的工作几乎完美，但出于某种原因，创建的视频是一个放大的动画在Matlab和我不知道为什么。

这是我的代码(用cspice忽略一切，这是接收空间中物体位置的工具箱)：

clear

%Load kernels
cspice_furnsh( 'de421.bsp' )
cspice_furnsh( 'MAR085.BSP' )
cspice_furnsh( 'maven_v03.tf' )
cspice_furnsh( 'MEX_130305_STEP.TSC' )
cspice_furnsh( 'MEX_V11.TF' )
cspice_furnsh( 'MVN_SCLKSCET.00000.tsc' )
cspice_furnsh( 'NAIF0010.TLS' )
cspice_furnsh( 'ORMF_______________00880.BSP' )
cspice_furnsh( 'PCK00010.TPC' )
cspice_furnsh( 'spk_m_141027-151027_110526.bsp')
cspice_furnsh( 'ORMM__150301000000_01138.BSP' )

% Flyby 09 APR 2015    
    ETbegin = cspice_str2et( '2015-04-09T06:30:00' );
    ETend = cspice_str2et( '2015-04-09T14:10:00' );

% Generation of calculation input array
    interval_ET=[ETbegin:1:ETend];

% Computation of positions of MAVEN, MEX and Phobos in reference to Mars
    position_MAVEN_Mars = cspice_spkpos...
        ( 'maven', interval_ET, 'J2000', 'none', 'mars' );
    position_MEX_Mars = cspice_spkpos...
        ( 'mex', interval_ET, 'J2000', 'none', 'mars' );
    position_Phobos_Mars = cspice_spkpos...
        ( 'phobos', interval_ET, 'J2000', 'none', 'mars' );

MEX_x = position_MEX_Mars(1,:);
MEX_y = position_MEX_Mars(2,:);
MEX_z = position_MEX_Mars(3,:);
MAVEN_x = position_MAVEN_Mars(1,:);
MAVEN_y = position_MAVEN_Mars(2,:);
MAVEN_z = position_MAVEN_Mars(3,:);
PHOBOS_x = position_Phobos_Mars(1,:);
PHOBOS_y = position_Phobos_Mars(2,:);
PHOBOS_z = position_Phobos_Mars(3,:);

writerObj = VideoWriter('video_flyby.avi');
writerObj.FrameRate = 30;
writerObj.Quality = 100;
open(writerObj);

figure
plot3(0,0,0,'ro-',MEX_x,MEX_y,MEX_z,'b',...
                  MAVEN_x,MAVEN_y,MAVEN_z,'r',...
                  PHOBOS_x,PHOBOS_y,PHOBOS_z,'k');
legend('Mars','MEX','MAVEN','Phobos');
xlabel('X-axis (km)');
ylabel('Y-axis (km)');
zlabel('Z-axis (km)');
xlim([-20000 20000]);
view([47.5 32]);
grid on;
hold on;
m1 = plot3(MEX_x(1),MEX_y(1),MEX_z(1),'b*','MarkerSize',10);
m2 = plot3(MAVEN_x(1),MAVEN_y(1),MAVEN_z(1),'r*','MarkerSize',10);
m3 = plot3(PHOBOS_x(1),PHOBOS_y(1),PHOBOS_z(1),'k*','MarkerSize',10);
axis tight
set(gca,'nextplot','replacechildren');
set(gcf,'Renderer','zbuffer');
for n = 1:100:numel(PHOBOS_x)
    set(m1, 'XData', MEX_x(n), 'YData', MEX_y(n), 'ZData', MEX_z(n));
    set(m2, 'XData', MAVEN_x(n), 'YData', MAVEN_y(n), 'ZData', MAVEN_z(n));
    set(m3, 'XData', PHOBOS_x(n), 'YData', PHOBOS_y(n), 'ZData', PHOBOS_z(n));
    drawnow;
    frame = getframe;
    writeVideo(writerObj,frame);
end

close(writerObj);

% Unload kernels
cspice_kclear;

这是Matlab中的结果。

​

这就是整个视频的样子。

​

Answer 1

如果使用不带参数的getframe，则只捕获当前轴。创建一个图形句柄，并将其作为参数提供给getframe。这样，您将捕获实际数字的所有内容。

以下是受影响的两条线，只是为了向您展示一下原理：

fh = figure;
frame = getframe(fh);