Adjusting width of horizontal colorbar

I have a horizontal colorbar that I want to set the width and keep centered under my figure. I've attempted to change the width element of the colorbar position attribute similar to below:

hcb=colorbar('SouthOutside');
x1=get(gca,'position');
colorbarpos=hcb.Position;
colorbarpos(4)=colorbarpos(4)*0.9;
set(hcb,'Position',colorbarpos);
set(ax,'position',x1);

While I'm able to shrink the height, oddly the width of the colorbar increases under the figure. Does anyone know how I might simply decrease the height of the horizontal colorbar while keeping the colorbar the same width as the figure above?

Answer 1

[Chunru]

ax1 = gca;
imagesc(peaks(80))

hcb=colorbar('SouthOutside');
ax1Pos = ax1.Position;

pos = hcb.Position;
pos(4) = 0.5*pos(4);
hcb.Position = pos;
% The above automatically change the ax1.Position
% We restore the origninal ax1.Position
ax1.Position = ax1Pos;

% x1=get(gca,'position');
% colorbarpos=hcb.Position;
% colorbarpos(4)=colorbarpos(4)*0.9;
% set(hcb,'Position',colorbarpos);
%set(ax,'position',x1);

[John Cruce]

I've tried this, but the width gets out of proportion (top image is the original, bottom has a modified colorbar):

Here's the code I'm using:

set(gcf,'units','pixel','position',[0,0,730,1300],'papersize',[730,1300],'color','w');
set(gca,'xtick',[],'xticklabel',[],'ytick',[],'yticklabel',[],'color','w');
m_proj('Miller Cylindrical','lon',[-92 -88],'lat',[28 32.5]);
ax=gca;
hcb=colorbar('SouthOutside');
hcb.Label.String='Test Color Bar';
axPos = ax.Position;
colorbarpos=hcb.Position;
colorbarpos(4)=0.4*colorbarpos(4);
hcb.Position = colorbarpos;
ax.Position = axPos;
m_grid('xtick',[],'ytick',[],'linestyle','none','backgroundcolor',[0.61961 0.73333 0.84314]);

[Chunru]

It might be caused by the custom functions m_proj and m_grid. Without them, everything works fine. You can try to move these two lines before "ax=gca;"

set(gcf,'units','pixel','position',[0,0,730,300],'papersize',[730,300],'color','w');
set(gca,'xtick',[],'xticklabel',[],'ytick',[],'yticklabel',[],'color','w');
%m_proj('Miller Cylindrical','lon',[-92 -88],'lat',[28 32.5]);
ax=gca;
hcb=colorbar('SouthOutside');
hcb.Label.String='Test Color Bar';
axPos = ax.Position;
colorbarpos=hcb.Position;
colorbarpos(4)=0.4*colorbarpos(4);
hcb.Position = colorbarpos;
ax.Position = axPos;

%m_grid('xtick',[],'ytick',[],'linestyle','none','backgroundcolor',[0.61961 0.73333 0.84314]);

[John Cruce]

I changed the figure size and that did the trick. Thank you.