Fast Models Reference Manual - ARM Information Center

Peripheral and Interface Components
In addition to the public method defined in VisRegion, this class defines the following:
VisRasterLayout const *lock()
Locks the region for client rendering. The VisRasterLayout structure is described
elsewhere. See Struct VisRasterLayout. While the buffer is locked, the client can
modify the pixel data for the buffer. You must not call the methods writeText()
and renderBitmap() while the buffer is locked.
void unlock()
This releases the lock on the render buffer, allowing the buffer to be updated on
screen.
void update(int left, int top, unsigned int width, unsigned int height)
This causes the specified rectangle to be drawn to the GUI.
int writeText(const char *text, int x, int y)
This renders the given ASCII text onto an unlocked VisRenderRegion. The return
value is the x co-ordinate of the end of the string. The default font is 8 pixels high,
and cannot be changed.
void renderBitmap(VisBitmap *bitmap, int x, int y)
Draws a bitmap onto an unlocked VisRenderRegion.
Struct VisRasterLayout
The VisRasterLayout struct defines the layout of the pixel data in a frame-buffer. The lock()
method of the LCD protocol expects to be given a pointer to this structure. You can generate a
suitable instance by calling VisRasterRegion::lock().
The structure contains the following fields:
uint8_t *buffer
This points to the buffer for the rasterized pixel data. The controller can write
pixels into this buffer, but must stick within the bounds specified by the width and
height.
uint32_t pitch
The number of bytes between consecutive raster lines in the pixel data. This can
be greater than the number of bytes per line.
uint32_t width
The width, in pixels, of the render area. This value can be less than the width
requested by the LCD controller when it called lock().
uint32_t height
The height, in pixels, of the render area. This value can be less than the height
requested by the LCD controller when it called lock().
VisPixelFormat format
This structure defines the format of the pixel data in the raster buffer.
bool changed
This is set to true if the pixel format or buffer size has changed since the previous
call to lock().
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