[cairo] Cairo Drawing Speed
Duong Hoang Linh
linh.duong at quantuminventions.com
Tue Nov 24 00:51:20 PST 2009
I think i used win32 surface. Below is the code for initializing my
cairo structure before drawing:
int ww, wh;
ww = (rc.right - rc.left);
wh = (rc.bottom - rc.top);
memdc = CreateCompatibleDC(paintDC.m_hDC);
hbuffer = CreateCompatibleBitmap(paintDC.m_hDC, ww, wh);
surface = cairo_win32_surface_create (memdc); // to the memory DC
cr = cairo_create (surface);
It may be a good idea to use image surface. I will try out and compare.
Maarten Bosmans wrote:
> Your code looks like the right way to construct these lines.
> What backend are you using? It could very well be that using an
> imagesurface to draw the lines and then blit the result to the screen
> is faster.
> And of course it is always faster if the lines are aligned on the
> pixel grid, but in your case that's probably not possible because of
> diagonal line segments.
> 2009/11/24 Duong Hoang Linh <linh.duong at quantuminventions.com>:
>> Hi Emmanuel,
>> This is my code for drawing line:
>> cairo_set_source_rgb (cr, 0, 0, 0);
>> cairo_set_line_width (cr, 7);
>> cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
>> cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
>> for(int k=0;k<vLines.size();k++)
>> cairo_move_to (cr, vLines[k].ptLineArray.x, vLines[k].ptLineArray.y);
>> for(int i=1;i<vLines[k].numLinePoints;i++)
>> cairo_line_to (cr, vLines[k].ptLineArray[i].x, vLines[k].ptLineArray[i].y);
>> cairo_stroke_preserve (cr);
>> cairo_set_source_rgb (cr, 1, 1, 1);
>> cairo_set_line_width (cr, 4);
>> cairo_stroke (cr);
>> I run this code on wince 5.0 device, processor ARM920T, 40MB RAM.
>> In more detail, i measure the time execution of cairo_stroke and it takes
>> from 100-120ms. And in total, i need to do cairo_stroke 6 times, which add
>> up to 700+ms.
More information about the cairo