Action
Start a continuous sketch update.
Syntax FT800
CmdSketch x, y, w, h, ptr, format
Syntax FT801
CmdSketch x, y, w, h, ptr, format , freq
Remarks
x |
x-coordinate of sketch area top-left, in pixels |
y |
y-coordinate of sketch area top-left, in pixels |
w |
Width of sketch area, in pixels |
h |
Height of sketch area, in pixels |
ptr |
Base address of sketch bitmap |
format |
Format of sketch bitmap, either L1 or L8 |
freq |
The oversampling frequency. The typical value is 1500 to make sure the lines are connected smoothly. The value zero means no oversampling operation. |
FT800
Please note that update frequency of bitmap data in graphics memory depends on sampling frequency of ADC built-in circuit of FT800, which is up to 1000 Hz.
FT801
CmdSketch - Capacitive touch specific sketch This command has the same functionality as CmdSketch except it has done the optimization for a Capacitive Touch Panel.
Because Capacitive Touch Panels have lower sampling frequencies (around 100 Hz) to report the coordinates, the sketch functionality updates less frequently compared to resistive touch. CmdSketch introduces a linear interpolation algorithm to provide a smoother effect when drawing the output line.
After the sketch command, the co-processor engine continuously samples the touch inputs and paints pixels into a bitmap, according to the touch (x, y). This means that the user touch inputs are drawn into the bitmap without any need for MCU work.
Command CmdStop stops the sketch process.
Note that only one of CmdSketch, CmdScreenSaver or CmdSpinner can be active at one time.
Example
' see demo - FT800 Sketch.bas also FT800 Demo4.bas (SUB Sketch)