What are the methods in the android canvas class

Commonly used methods in the android canvas class include drawing basic graphics, drawing paths, drawing text, drawing images, processing colors and styles, processing matrices, drawing shadows, etc. Detailed introduction: 1. Draw basic graphics: drawRect: draw a rectangle; drawRoundRect: draw a rounded rectangle; drawCircle: draw a circle; drawOval: draw an ellipse; drawLine: draw a straight line; drawPath: draw a Path object; 2. Draw path methods, etc. .

Operating system for this tutorial: Windows 10 system, Dell G3 computer.

The Android Canvas class is a class used for drawing graphics and processing images. It is located in the android.graphics package. The Canvas class provides a series of methods to draw various shapes, paths, text, and images, as well as handle colors, styles, matrices, etc. The following are some commonly used methods in the Canvas class:

1. Draw basic graphics:

   • drawRect(RectF rect, Paint paint): Draw a rectangle.
   • drawRoundRect(RectF rect, float rx, float ry, Paint paint): Draw a rounded rectangle.
   • drawCircle(float x, float y, float radius, Paint paint): Draw a circle.
   • drawOval(RectF oval, Paint paint): Draw an ellipse.
   • drawLine(float x1, float y1, float x2, float y2, Paint paint): Draw a straight line.
   • drawPath(Path path, Paint paint): Draw Path object.

2. Draw path:

   • drawPath(Path path, Paint paint): Draw the Path object.
   • drawPath(Path path, Paint paint, PathEffect pathEffect): Draw the Path object and apply PathEffect.
   • drawRect(RectF rect, Paint paint, Path path): Draw Path within the given rectangular area.

3. Draw text:

   • drawText(CharSequence text, float x, float y, Paint paint): Draw text at the specified position.
   • drawText(CharSequence text, float x, float y, Paint paint, Paint.Align align): Draw text at the specified position and specify the text alignment.
   • drawTextOnPath(CharSequence text, Path path, float hAlign, float vAlign, Paint paint): Draw text on the given path.

4. Draw an image:

   • drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint): Draw a Bitmap image.
   • drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint, Matrix matrix): Draw a Bitmap image and apply matrix transformation.
   • drawBitmap(Bitmap bitmap, float x, float y, Paint paint): Draw a Bitmap image at the specified position.
   • drawBitmap(Bitmap bitmap, float x, float y, Paint paint, Matrix matrix): Draw a Bitmap image at the specified position and apply matrix transformation.

5. Handling colors and styles:

   • setColor(int color): Set the brush color.
   • setStrokeWidth(float width): Set the brush width.
   • setStyle(Paint.Style style): Set the brush style (such as solid line, dotted line, etc.).
   • setAntiAlias(boolean aa): Set the anti-aliasing effect.
   • setColorFilter(ColorFilter cf): Set the color filter.

6. Processing matrix:

   • setMatrix(Matrix matrix): Set the current matrix.
   • getMatrix(Matrix matrix): Get the current matrix.
   • translate(float dx, float dy): Translate the current matrix.
   • scale(float scaleX, float scaleY): Scale the current matrix.
   • rotate(float degrees): Rotate the current matrix.
   • skew(float sx, float sy): Skew the current matrix.

7. Draw shadow:

   • drawRect(RectF rect, Paint paint, float radius): Draw a rectangle with shadow.
   • drawRoundRect(RectF rect, float rx, float ry, Paint paint, float radius): Draw a rounded rectangle with shadow.

This is only a part of the methods of the Canvas class. In fact, the Canvas class provides many other methods to handle different drawing tasks. To learn more about the methods of the Canvas class, please refer to the official Android documentation: https://developer.android.com/reference/android/graphics/Canvas

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