floodFill
import { floodFill } from '@banou/opencv-wasm'Use after await initOpenCV(). See the initialization and named imports guide.
Fills a connected component with the given color.
The function cv::floodFill fills a connected component starting from the seed point with the specified
color. The connectivity is determined by the color/brightness closeness of the neighbor pixels. The
pixel at (x,y) is considered to belong to the repainted domain if:
- in case of a grayscale image and floating range
\texttt{src} (x',y')- \texttt{loDiff} \leq \texttt{src} (x,y) \leq \texttt{src} (x',y')+ \texttt{upDiff}
- in case of a grayscale image and fixed range
\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)- \texttt{loDiff} \leq \texttt{src} (x,y) \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)+ \texttt{upDiff}
- in case of a color image and floating range
\texttt{src} (x',y')_r- \texttt{loDiff} _r \leq \texttt{src} (x,y)_r \leq \texttt{src} (x',y')_r+ \texttt{upDiff} _r,
\texttt{src} (x',y')_g- \texttt{loDiff} _g \leq \texttt{src} (x,y)_g \leq \texttt{src} (x',y')_g+ \texttt{upDiff} _g
and
\texttt{src} (x',y')_b- \texttt{loDiff} _b \leq \texttt{src} (x,y)_b \leq \texttt{src} (x',y')_b+ \texttt{upDiff} _b
- in case of a color image and fixed range
\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_r- \texttt{loDiff} _r \leq \texttt{src} (x,y)_r \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_r+ \texttt{upDiff} _r,
\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_g- \texttt{loDiff} _g \leq \texttt{src} (x,y)_g \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_g+ \texttt{upDiff} _g
and
\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_b- \texttt{loDiff} _b \leq \texttt{src} (x,y)_b \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_b+ \texttt{upDiff} _b
where src(x',y') is the value of one of pixel neighbors that is already known to belong to the
component. That is, to be added to the connected component, a color/brightness of the pixel should
be close enough to:
- Color/brightness of one of its neighbors that already belong to the connected component in case of a floating range.
- Color/brightness of the seed point in case of a fixed range.
Use these functions to either mark a connected component with the specified color in-place, or build a mask and then extract the contour, or copy the region to another image, and so on.
Note: Since the mask is larger than the filled image, a pixel (x, y) in image corresponds to the
pixel (x+1, y+1) in the mask .
See: findContours
floodFill(image: Mat, seedPoint: Mat, newVal: Point, rect: Scalar): number;5 available overloads
floodFill(image: Mat, mask: Mat, seedPoint: Point, newVal: Scalar, rect: Rect, loDiff: Scalar, upDiff: Scalar, flags: number): number;floodFill(image: Mat, seedPoint: Mat, newVal: Point, rect: Scalar, loDiff: Rect, upDiff: Scalar, flags: Scalar): number;floodFill(image: Mat, seedPoint: Mat, newVal: Point, rect: Scalar, loDiff: Rect, upDiff: Scalar): number;floodFill(image: Mat, seedPoint: Mat, newVal: Point, rect: Scalar, loDiff: Rect): number;floodFill(image: Mat, seedPoint: Mat, newVal: Point, rect: Scalar): number;imageInput/output value, modified by the native operation. Input/output 1- or 3-channel, 8-bit, or floating-point image. It is modified by the function unless the #FLOODFILL_MASK_ONLY flag is set in the second variant of the function. See the details below.
maskInput/output value, modified by the native operation. Operation mask that should be a single-channel 8-bit image, 2 pixels wider and 2 pixels taller than image. If an empty Mat is passed it will be created automatically. Since this is both an input and output parameter, you must take responsibility of initializing it. Flood-filling cannot go across non-zero pixels in the input mask. For example, an edge detector output can be used as a mask to stop filling at edges. On output, pixels in the mask corresponding to filled pixels in the image are set to 1 or to the specified value in flags as described below. Additionally, the function fills the border of the mask with ones to simplify internal processing. It is therefore possible to use the same mask in multiple calls to the function to make sure the filled areas do not overlap.
seedPointStarting point.
newValNew value of the repainted domain pixels.
rectOutput destination, filled by the native operation. Optional output parameter set by the function to the minimum bounding rectangle of the repainted domain.
loDiffMaximal lower brightness/color difference between the currently observed pixel and one of its neighbors belonging to the component, or a seed pixel being added to the component.
upDiffMaximal upper brightness/color difference between the currently observed pixel and one of its neighbors belonging to the component, or a seed pixel being added to the component.
flagsOperation flags. The first 8 bits contain a connectivity value. The default value of 4 means that only the four nearest neighbor pixels (those that share an edge) are considered. A connectivity value of 8 means that the eight nearest neighbor pixels (those that share a corner) will be considered. The next 8 bits (8-16) contain a value between 1 and 255 with which to fill the mask (the default value is 1). For example, 4 | ( 255 << 8 ) will consider 4 nearest neighbours and fill the mask with a value of 255. The following additional options occupy higher bits and therefore may be further combined with the connectivity and mask fill values using bit-wise or (|), see #FloodFillFlags.
The number result.
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