In ps, the method of gradually thickening or thinning the curve is: through the method of path stroke. The specific operation method is:

1. Select the pen tool and select the path of tool properties, as shown in the following figure:

2. Draw a curve path, as shown below:

3. Stroke preparation: set the size and color of the brush, select the brush tool-enter the switch brush panel, set the following figure, and set the control to pen pressure in shape dynamics.

4. Path Stroke: Select Pen Tool-Right-click Path-Stroke Path, as shown below:

5. Select a brush for the stroke tool and check the simulated pressure, as shown in the following figure:

6. After confirming and deleting the path, the effect is as follows: