gca

Current axes or chart

Syntax

ax = gca

Description

ax = gca returns the current axes or chart for the current figure, which is typically the last one created or clicked with the mouse.

ax = gca  返回當前圖形的當前軸或圖表，通常是用滑鼠建立或單擊的最後一個軸。

Graphics functions, such as title, target the current axes or chart. Use ax

圖形功能（例如標題）以當前軸或圖表為目標。 使用ax訪問和修改軸或圖表的屬性。 如果軸或圖表不存在，則gca建立笛卡爾座標軸。

Specify Properties for Current Axes

Plot a sine wave. 

x = linspace(0,10);
y = sin(4*x);
plot(x,y)

Set the font size, tick direction, tick length, and y-axis limits for the current axes. Use gca to refer to the current axes. 
Note: Starting in R2014b, you can use dot notation to set properties. If you are using an earlier release, use the docid:matlab_ref.f67-432995 function instead, such as set(ax,'FontSize',12).

ax = gca; % current axes
ax.FontSize = 12;
ax.TickDir = 'out';
ax.TickLength = [0.02 0.02];
ax.YLim = [-2 2];

Tips

• User interaction can change the current axes or chart. It is better to assign the axes or chart to a variable when you create it instead of relying on gca.

• 使用者互動可以更改當前軸或圖表。 最好在建立變數時將軸或圖表分配給變數，而不是依賴於gca。

• Changing the current figure also changes the current axes or chart.

• 更改當前圖形也會更改當前軸或圖表。

• Set axes properties after plotting since some plotting functions reset axes properties.

• 繪圖後設置軸屬性，因為某些繪圖功能會重置軸屬性。

• To access the current axes or chart without forcing the creation of Cartesian axes, query the figure CurrentAxes property. MATLAB® returns an empty array if there is no current axes.

• 要在不強制建立笛卡爾座標軸的情況下訪問當前軸或圖表，請查詢圖形CurrentAxes屬性。 如果沒有當前軸，MATLAB®將返回一個空陣列。

  fig = gcf; ax = fig.CurrentAxes;Starting in R2014b, you can query properties using dot notation. If you are using an earlier release, use the get function instead, such as ax = get(fig,'CurrentAxes').
• 從R2014b開始，您可以使用點表示法查詢屬性。 如果您使用的是早期版本，請改用get函式，例如ax = get(fig,'CurrentAxes').

上例中，如果加入語句：

fig = gcf; ax = fig.CurrentAxes;

則得到：

ax = 

  Axes - 屬性:

             XLim: [0 2]
             YLim: [-100 20]
           XScale: 'linear'
           YScale: 'linear'
    GridLineStyle: '-'
         Position: [0.1300 0.1100 0.7750 0.8150]
            Units: 'normalized'