Draw functions

This section provides an overview of the draw functions.

vg_lite_draw function

Description:

This function performs a hardware accelerated 2D vector draw operation.

The size of the tessellation buffer can be specified at initialization and it is aligned with the minimum hardware alignment requirements of the kernel. Specifying a smaller size for tessellation buffer allocates less memory but reduces performance. Because the hardware walks the target with the provided tessellation window size, a path may be sent to the hardware multiple times. It is a good practice to set the tessellation buffer size to the most common path size. For example, if all you do is render up to 24-point fonts, you can set the tessellation buffer to 24x24.

Note:

• All the color formats available in the vg_lite_buffer_format_t enum are supported as the destination buffer for the draw function

• The hardware does not support strokes; they must be converted to paths before you use them in the draw API

Syntax:

vg_lite_error_t vg_lite_draw (
       vg_lite_buffer_t         *target,
       vg_lite_path_t           *path,
       vg_lite_fill_t           fill_rule,
       vg_lite_matrix_t         *matrix,
       vg_lite_blend_t          blend,
       vg_lite_color_t          color
);

Parameters:

Parameter	Description
*target	Pointer to the vg_lite_buffer_t structure for the destination buffer. All color formats available in the vg_lite_buffer_format_t enum are valid destination formats for the draw function.
*path	Pointer to the vg_lite_path_t structure containing path data that describes the path to draw. See opcode details in Vector path opcodes for plotting paths.
fill_rule	Specifies the vg_lite_fill_t enum value for the fill rule for the path
*matrix	Pointer to a vg_lite_matrix_t structure that defines the affine transformation matrix of the path. If the matrix is NULL, an identity matrix is assumed. Note: Non-affine transformations are not supported by vg_lite_draw; therefore, a perspective transformation matrix might have unexpected effects on path rendering.
blend	Select one of the hardware-supported blend modes in the vg_lite_blend_t enum to be applied to each drawn pixel. If no blending is required, set this value to VG_LITE_BLEND_NONE (0).
color	The color applied to each pixel drawn by the path.

Returns:

Returns VG_LITE_SUCCESS if successful. See vg_lite_error_t enum for other return codes.

Parent topic:Draw functions

vg_lite_draw_grad function

Description:

This function is used to fill a path with a linear gradient according to the specified fill rules. The specified path is transformed according to the selected matrix and is filled with the specified color gradient.

Syntax:

vg_lite_error_t vg_lite_draw_grad (
    vg_lite_buffer_t            *target,
    vg_lite_path_t              *path, 
    vg_lite_fill_t              fill_rule, 
    vg_lite_matrix_t            *matrix, 
    vg_lite_linear_gradient_t   *grad, 
    vg_lite_blend_t             blend
);  

Parameters:

Parameter	Description
*target	Pointer to the vg_lite_buffer_t structure containing data describing the target path.
*path	Pointer to the vg_lite_path_t structure containing path data that describes the path to draw and fill with the linear gradient. See opcode details in Vector path opcodes for plotting paths.
fill_rule	Specifies the vg_lite_fill_t enum value for the fill rule for the path
*matrix	Pointer to the vg_lite_matrix_t structure that defines the 3x3 transformation matrix of the path. If the matrix is NULL, an identity matrix is assumed; however, this option is not preferable.
*grad	Pointer to the vg_lite_linear_gradient_t structure that contains the values to be used to fill the path.
blend	Specifies the blend mode in the vg_lite_blend_t enum to be applied to each drawn pixel. If no blending is required, set this value to VG_LITE_BLEND_NONE (0).

Returns:

Returns VG_LITE_SUCCESS if successful. See vg_lite_error_t enum for other return codes.

Parent topic:Draw functions

vg_lite_draw_radial_grad function

Description:

This function is used to fill a path with a radial gradient according to the specified fill rules. The specified path is transformed according to the selected matrix and is filled with the radial color gradient. The application can use VGLite API vg_lite_query_feature (gcFEATURE_BIT_VG_RADIAL_GRADIENT) to determine HW support for radial gradient.

Syntax:

vg_lite_error_t vg_lite_draw_radial_grad (
    vg_lite_buffer_t            *target,
    vg_lite_path_t              *path, 
    vg_lite_fill_t              fill_rule, 
    vg_lite_matrix_t            *path_matrix, 
    vg_lite_radial_gradient_t   *grad,
    vg_lite_color_t             paint_color,
    vg_lite_blend_t             blend,
    vg_lite_filter_t            filter
);  

Parameters:

Parameter	Description
*target	Pointer to the vg_lite_buffer_t structure containing data describing the target path.
*path	Pointer to the vg_lite_path_t structure containing path data that describes the path to draw for and fill with the radial gradient. See opcode details in Vector path opcodes for plotting paths.
fill_rule	Specifies the vg_lite_fill_t enum value for the fill rule for the path
*path_matrix	Pointer to a vg_lite_matrix_t structure that defines the 3x3 transformation matrix of the path. If the matrix is NULL, an identity matrix is assumed; however, his option is not preferable.
*grad	Pointer to the vg_lite_radial_gradient_t structure that contains the values to be used to fill the path. Note: grad->image.image_mode does not support VG_LITE_MULTIPLY_IMAGE_MODE .
paint_color	Specifies the paint color vg_lite_color_t RGBA value to be applied by VG_LITE_RADIAL_GRADIENT_SPREAD_FILL set by the function vg_lite_set_radial_grad. When pixels are out of the image after transformation, paint_color is applied to them. For details, see vg_lite_radial_gradient_spreadmode_t.
blend	Specifies the blend mode in the vg_lite_blend_t enum to be applied to each drawn pixel. If no blending is required, set this value to VG_LITE_BLEND_NONE (0).
filter	Specified the filter mode vg_lite_filter_t enum value to be applied to each drawn pixel. If no filtering is required, set this value to VG_LITE_BLEND_POINT (0).

Returns:

Returns VG_LITE_SUCCESS if successful. See vg_lite_error_t enum for other return codes.

Parent topic:Draw functions

vg_lite_draw_pattern function

Description:

This function fills a path with an image pattern. The path is transformed according to the specified matrix and is filled with the transformed image pattern.

Syntax:

vg_lite_error_t vg_lite_draw_pattern (
    vg_lite_buffer_t            *target,
    vg_lite_path_t              *path,
    vg_lite_fill_t              fill_rule,
    vg_lite_matrix_t            *path_matrix,
    vg_lite_buffer_t            *pattern_image,
    vg_lite_matrix_t            *pattern_matrix,
    vg_lite_blend_t             blend,
    vg_lite_pattern_mode_t      pattern_mode,
    vg_lite_color_t             pattern_color,
    vg_lite_color_t             color,
    vg_lite_filter_t            filter
);

Parameters:

Parameter	Description
*target	Pointer to the vg_lite_buffer_t structure for the destination buffer. All color formats available in the vg_lite_buffer_format_t enum are valid destination formats for this draw function.
*path	Pointer to the vg_lite_path_t structure containing path data that describes the path to draw. See opcode details in Vector path opcodes for plotting paths
fill_rule	Specifies the vg_lite_fill_t enum value for the fill rule for the path.
*path_matrix	Pointer to the vg_lite_matrix_t structure that defines the 3x3 transformation matrix of the source pixels into the target. If the matrix is NULL, an identity matrix is assumed, meaning the source is copied directly onto the target at 0,0 location.
*pattern_image	Pointer to a vg_lite_matrix_t structure that defines the 3x3 transformation matrix of the path. If the matrix is NULL, an identity matrix is assumed.
*pattern_matrix	Pointer to the vg_lite_buffer_t structure that describes the source of the image pattern
	Pointer to a vg_lite_matrix_t structure that defines the 3x3 transformation matrix of the source pixels into the target. If the matrix is NULL, an identity matrix is assumed, which means that the source is copied directly at 0,0 location on the target.
blend	Specifies one of the vg_lite_blend_t enum values for hardware-supported blend modes to be applied to each drawn pixel in the image. If no blending is required, set this value to VG_LITE_BLEND_NONE (0).
pattern_mode	Specifies the vg_lite_pattern_mode_t value that defines how the region outside the image pattern is to be filled.
pattern_color	Specifies a 32bpp ARGB color (vg_lite_color_t) to be applied to the fill outside the image pattern area when the pattern_mode value is VG_LITE_PATTERN_COLOR. (from Dec 2019, type now vg_lite_color_t, previously was uint32_t)
color	Specifies a 32bpp ARGB color (vg_lite_color_t) to be applied as a mix color. If non-zero, the mix color value gets multiplied with each source pixel before blending happens. If a mix color is not needed, set the color parameter to 0 (from May 2023). Note: This parameter has no effect if the pattern image vg_lite_buffer_t structure member image_mode is set to VG_LITE_ZERO or VG_LITE_NORMAL_IMAGE_MODE.
filter	Specifies the filter type. All formats available in the vg_lite_filter_t enum are valid formats for this function. A value of zero (0) indicates VG_LITE_FILTER_POINT.

Returns:

Returns VG_LITE_SUCCESS if successful. See vg_lite_error_t enum for other return codes.

Parent topic:Draw functions

Parent topic:Vector-dased draw operations