What does top, left, right and bottom mean in Android Rect object

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情书的邮戳
情书的邮戳 2021-01-29 22:18

I have an Android project where I should make Apples fall. The apples are painted in a Rect. So I created a function that change the Rect position and repaint. Here\'s my functi

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  • 2021-01-29 22:24

    This image will explain you in detail:

    enter image description here

    left The X coordinate of the left side of the rectangle

    top The Y coordinate of the top of the rectangle

    right The X coordinate of the right side of the rectangle

    bottom The Y coordinate of the bottom of the rectangle

    enter image description here

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  • 2021-01-29 22:37

    From the docs

    Parameters

    left The X coordinate of the left side of the rectangle

    top The Y coordinate of the top of the rectangle

    right The X coordinate of the right side of the rectangle

    bottom The Y coordinate of the bottom of the rectangle

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  • 2021-01-29 22:46

    Adding a crucial information.

    The documentation says:

    Note that the right and bottom coordinates are exclusive.

    So if your rectangle is a single pixel at position 10,10

    left = 10 : The X coordinate of the left side of the rectangle

    top = 10 : The Y coordinate of the top of the rectangle = 10

    right = 11 : The X coordinate of the right side of the rectangle plus one

    bottom = 11 : The Y coordinate of the bottom of the rectangle plus one

    Note that the right and bottom coordinates are exclusive.

    The methods getWidth is declared as such

    public final int width() { return right - left; }

    Here it will return 11 - 10 = 1, as expected.

    https://developer.android.com/reference/android/graphics/Rect

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