tv
— tv shield driver¶
The tv
module is used for controlling the tv shield.
Example usage:
import sensor, tv
# Setup camera.
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.SIF)
sensor.skip_frames()
tv.init()
# Show image.
while(True):
tv.display(sensor.snapshot())
Functions¶
- tv.init([type=tv.TV_SHIELD[, triple_buffer=False]])¶
Initializes an attached tv output module.
type
indicates how the lcd module should be initialized:tv.TV_NONE
: Do nothing.tv.TV_SHIELD
: Initialize a TV output module. Uses pins P0, P1, P2, and P3.
triple_buffer
If True then makes updates to the screen non-blocking intv.TV_SHIELD
mode at the cost of 3X the display RAM (495 KB).
- tv.deinit()¶
Deinitializes the tv module, internal/external hardware, and I/O pins.
- tv.width()¶
Returns 352 pixels. This is the
sensor.SIF
resolution.
- tv.height()¶
Returns 240 pixels. This is the
sensor.SIF
resolution.
- tv.refresh()¶
Returns 60 Hz.
- tv.channel([channel])¶
For the wireless TV shield this sets the broadcast channel between 1-8. If passed without a channel argument then this method returns the previously set channel (1-8). Default is channel 8.
- tv.display(image[, x=0[, y=0[, x_scale=1.0[, y_scale=1.0[, roi=None[, rgb_channel=-1[, alpha=256[, color_palette=None[, alpha_palette=None[, hint=0[, x_size=None[, y_size=None]]]]]]]]]]]])¶
Displays an
image
whose top-left corner starts at location x, y. You may either pass x, y separately, as a tuple (x, y), or neither.x_scale
controls how much the displayed image is scaled by in the x direction (float). If this value is negative the image will be flipped horizontally.y_scale
controls how much the displayed image is scaled by in the y direction (float). If this value is negative the image will be flipped vertically.roi
is the region-of-interest rectangle tuple (x, y, w, h) of the image to display. This allows you to extract just the pixels in the ROI to scale.rgb_channel
is the RGB channel (0=R, G=1, B=2) to extract from an RGB565 image (if passed) and to render on the display. For example, if you passrgb_channel=1
this will extract the green channel of the RGB565 image and display that in grayscale.alpha
controls how opaque the image is. A value of 256 displays an opaque image while a value lower than 256 produces a black transparent image. 0 results in a perfectly black image.color_palette
if not-1
can besensor.PALETTE_RAINBOW
,sensor.PALETTE_IRONBOW
, or a 256 pixel in total RGB565 image to use as a color lookup table on the grayscale value of whatever the input image is. This is applied afterrgb_channel
extraction if used.alpha_palette
if not-1
can be a 256 pixel in total GRAYSCALE image to use as a alpha palette which modulates thealpha
value of the input image being displayed at a pixel pixel level allowing you to precisely control the alpha value of pixels based on their grayscale value. A pixel value of 255 in the alpha lookup table is opaque which anything less than 255 becomes more transparent until 0. This is applied afterrgb_channel
extraction if used.hint
can be a logical OR of the flags:image.AREA
: Use area scaling when downscaling versus the default of nearest neighbor.image.BILINEAR
: Use bilinear scaling versus the default of nearest neighbor scaling.image.BICUBIC
: Use bicubic scaling versus the default of nearest neighbor scaling.image.CENTER
: Center the image image being displayed on (x, y).image.EXTRACT_RGB_CHANNEL_FIRST
: Do rgb_channel extraction before scaling.image.APPLY_COLOR_PALETTE_FIRST
: Apply color palette before scaling.
x_size
may be passed ifx_scale
is not passed to specify the size of the image to display andx_scale
will automatically be determined passed on the input image size. If neithery_scale
ory_size
are specified theny_scale
internally will be set to be equal tox_size
to maintain the aspect-ratio.y_size
may be passed ify_scale
is not passed to specify the size of the image to display andy_scale
will automatically be determined passed on the input image size. If neitherx_scale
orx_size
are specified thenx_scale
internally will be set to be equal toy_size
to maintain the aspect-ratio.
Constants¶
- tv.TV_SHIELD¶
Used to initialize the TV module.