44 lines
1.2 KiB
Python
44 lines
1.2 KiB
Python
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CANVAS_WIDTH = 50
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CANVAS_HEIGHT = 50
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LV_COLOR_CHROMA_KEY = lv.color_hex(0x00ff00)
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def LV_IMG_BUF_SIZE_ALPHA_1BIT(w, h):
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return int(((w / 8) + 1) * h)
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def LV_IMG_BUF_SIZE_INDEXED_1BIT(w, h):
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return LV_IMG_BUF_SIZE_ALPHA_1BIT(w, h) + 4 * 2
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def LV_CANVAS_BUF_SIZE_INDEXED_1BIT(w, h):
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return LV_IMG_BUF_SIZE_INDEXED_1BIT(w, h)
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#
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# Create a transparent canvas with Chroma keying and indexed color format (palette).
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#
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# Create a button to better see the transparency
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btn=lv.btn(lv.scr_act())
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# Create a buffer for the canvas
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cbuf= bytearray(LV_CANVAS_BUF_SIZE_INDEXED_1BIT(CANVAS_WIDTH, CANVAS_HEIGHT))
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# Create a canvas and initialize its palette
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canvas = lv.canvas(lv.scr_act())
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canvas.set_buffer(cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, lv.img.CF.INDEXED_1BIT)
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canvas.set_palette(0, LV_COLOR_CHROMA_KEY)
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canvas.set_palette(1, lv.palette_main(lv.PALETTE.RED))
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# Create colors with the indices of the palette
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c0 = lv.color_t()
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c1 = lv.color_t()
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c0.full = 0
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c1.full = 1
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# Red background (There is no dedicated alpha channel in indexed images so LV_OPA_COVER is ignored)
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canvas.fill_bg(c1, lv.OPA.COVER)
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# Create hole on the canvas
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for y in range(10,30):
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for x in range(5,20):
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canvas.set_px(x, y, c0)
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