/**
* Scrolls the given image across the display, from right to left.
* Returns immediately, and executes the animation asynchronously.
*
* @param image The image to display.
*
* @param delay The time between updates, in milliseconds. Defaults
* to: MICROBIT_DEFAULT_SCROLL_SPEED.
*
* @param stride The number of pixels to shift by in each update. Defaults to MICROBIT_DEFAULT_SCROLL_STRIDE.
*
* @return MICROBIT_OK, MICROBIT_BUSY if the display is already in use, or MICROBIT_INVALID_PARAMETER.
*
* @code
* MicrobitImage i("1,1,1,1,1\n1,1,1,1,1\n");
* display.scrollAsync(i,100,1);
* @endcode
*/
int MicroBitDisplay::scrollAsync(MicroBitImage image, int delay, int stride)
{
//sanitise the delay value
if(delay <= 0)
return MICROBIT_INVALID_PARAMETER;
// If the display is free, it's our turn to display.
if (animationMode == ANIMATION_MODE_NONE || animationMode == ANIMATION_MODE_STOPPED)
{
scrollingImagePosition = stride < 0 ? width : -image.getWidth();
scrollingImageStride = stride;
scrollingImage = image;
scrollingImageRendered = false;
animationDelay = stride == 0 ? 0 : delay;
animationTick = 0;
animationMode = ANIMATION_MODE_SCROLL_IMAGE;
}
else
{
return MICROBIT_BUSY;
}
return MICROBIT_OK;
}
/**
* Pastes a given bitmap at the given co-ordinates.
*
* Any pixels in the relevant area of this image are replaced.
*
* @param image The MicroBitImage to paste.
*
* @param x The leftmost X co-ordinate in this image where the given image should be pasted. Defaults to 0.
*
* @param y The uppermost Y co-ordinate in this image where the given image should be pasted. Defaults to 0.
*
* @param alpha set to 1 if transparency clear pixels in given image should be treated as transparent. Set to 0 otherwise. Defaults to 0.
*
* @return The number of pixels written.
*
* @code
* const uint8_t heart[] = { 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, }; // a cute heart
* MicroBitImage i(10,5,heart); // a big heart
* i.paste(i, -5, 0); // a small heart
* @endcode
*/
int MicroBitImage::paste(const MicroBitImage &image, int16_t x, int16_t y, uint8_t alpha)
{
uint8_t *pIn, *pOut;
int cx, cy;
int pxWritten = 0;
// Sanity check.
// We permit writes that overlap us, but ones that are clearly out of scope we can filter early.
if (x >= getWidth() || y >= getHeight() || x+image.getWidth() <= 0 || y+image.getHeight() <= 0)
return 0;
//Calculate the number of byte we need to copy in each dimension.
cx = x < 0 ? min(image.getWidth() + x, getWidth()) : min(image.getWidth(), getWidth() - x);
cy = y < 0 ? min(image.getHeight() + y, getHeight()) : min(image.getHeight(), getHeight() - y);
// Calculate sane start pointer.
pIn = image.ptr->data;
pIn += (x < 0) ? -x : 0;
pIn += (y < 0) ? -image.getWidth()*y : 0;
pOut = getBitmap();
pOut += (x > 0) ? x : 0;
pOut += (y > 0) ? getWidth()*y : 0;
// Copy the image, stride by stride
// If we want primitive transparecy, we do this byte by byte.
// If we don't, use a more efficient block memory copy instead. Every little helps!
if (alpha)
{
for (int i=0; i<cy; i++)
{
for (int j=0; j<cx; j++)
{
// Copy this byte if appropriate.
if (*(pIn+j) != 0){
*(pOut+j) = *(pIn+j);
pxWritten++;
}
}
pIn += image.getWidth();
pOut += getWidth();
}
}
else
{
for (int i=0; i<cy; i++)
{
memcpy(pOut, pIn, cx);
pxWritten += cx;
pIn += image.getWidth();
pOut += getWidth();
}
}
return pxWritten;
}