Cairo
2D graphics library with support for multiple output devices. It can be used to draw on multiple different surfaces, such as the FB graphics window, in-memory pixel buffers, a GTK+ widget or a Win32 window or device context.
Website: http://www.cairographics.org
Platforms supported: Win32, Linux
Headers to include: cairo/cairo.bi
Header version: 1.14.2
Examples: yes, in examples/graphics/cairo/
The framebuffer example was checked with the real Cairo 1.18.4 SDK on Win32 and Win64. The framebuffer is borrowed by cairo_image_surface_create_for_data and must remain valid until the surface is destroyed. Use the actual pitch returned by ScreenInfo.
Cairo error objects can be non-null. Check cairo_surface_status and cairo_status before drawing and after completion. Hold ScreenLock during framebuffer writes and flush the surface before making the result visible. Release both the drawing context and the caller's surface reference; destroying the context alone retains that surface reference.
last reviewed: MrSwiss, 2018-05-05 -- changed: SizeOf(Integer) to SizeOf(ULong) reason: 32/64 compatibility
Website: http://www.cairographics.org
Platforms supported: Win32, Linux
Headers to include: cairo/cairo.bi
Header version: 1.14.2
Examples: yes, in examples/graphics/cairo/
The framebuffer example was checked with the real Cairo 1.18.4 SDK on Win32 and Win64. The framebuffer is borrowed by cairo_image_surface_create_for_data and must remain valid until the surface is destroyed. Use the actual pitch returned by ScreenInfo.
Cairo error objects can be non-null. Check cairo_surface_status and cairo_status before drawing and after completion. Hold ScreenLock during framebuffer writes and flush the surface before making the result visible. Release both the drawing context and the caller's surface reference; destroying the context alone retains that surface reference.
Example
'' Example showing cairo being used to draw into the FB graphics window
#include Once "cairo/cairo.bi"
Const SCREEN_W = 400
Const SCREEN_H = 300
If ScreenRes(SCREEN_W, SCREEN_H, 32) <> 0 Then End 1
Dim image_pitch As Long
ScreenInfo , , , , image_pitch
'' Create a cairo drawing context, using the FB screen as surface.
Var surface = cairo_image_surface_create_for_data(ScreenPtr(), CAIRO_FORMAT_ARGB32, SCREEN_W, SCREEN_H, image_pitch)
If cairo_surface_status(surface) <> CAIRO_STATUS_SUCCESS Then
cairo_surface_destroy(surface)
End 1
End If
Var c = cairo_create(surface)
If cairo_status(c) <> CAIRO_STATUS_SUCCESS Then
cairo_destroy(c)
cairo_surface_destroy(surface)
End 1
End If
ScreenLock()
'' Draw the entire context white.
cairo_set_source_rgba(c, 1, 1, 1, 1)
cairo_paint(c)
'' Draw a red line
cairo_set_line_width(c, 1)
cairo_set_source_rgba(c, 1, 0, 0, 1)
cairo_move_to(c, 0, 0)
cairo_line_to(c, SCREEN_W - 1, SCREEN_H - 1)
cairo_stroke(c)
cairo_surface_flush(surface)
Dim draw_status As cairo_status_t = cairo_status(c)
ScreenUnlock()
If draw_status <> CAIRO_STATUS_SUCCESS Then
cairo_destroy(c)
cairo_surface_destroy(surface)
End 1
End If
Sleep
'' Clean up the cairo context
cairo_destroy(c)
cairo_surface_destroy(surface)
'' end of cairo.bas
#include Once "cairo/cairo.bi"
Const SCREEN_W = 400
Const SCREEN_H = 300
If ScreenRes(SCREEN_W, SCREEN_H, 32) <> 0 Then End 1
Dim image_pitch As Long
ScreenInfo , , , , image_pitch
'' Create a cairo drawing context, using the FB screen as surface.
Var surface = cairo_image_surface_create_for_data(ScreenPtr(), CAIRO_FORMAT_ARGB32, SCREEN_W, SCREEN_H, image_pitch)
If cairo_surface_status(surface) <> CAIRO_STATUS_SUCCESS Then
cairo_surface_destroy(surface)
End 1
End If
Var c = cairo_create(surface)
If cairo_status(c) <> CAIRO_STATUS_SUCCESS Then
cairo_destroy(c)
cairo_surface_destroy(surface)
End 1
End If
ScreenLock()
'' Draw the entire context white.
cairo_set_source_rgba(c, 1, 1, 1, 1)
cairo_paint(c)
'' Draw a red line
cairo_set_line_width(c, 1)
cairo_set_source_rgba(c, 1, 0, 0, 1)
cairo_move_to(c, 0, 0)
cairo_line_to(c, SCREEN_W - 1, SCREEN_H - 1)
cairo_stroke(c)
cairo_surface_flush(surface)
Dim draw_status As cairo_status_t = cairo_status(c)
ScreenUnlock()
If draw_status <> CAIRO_STATUS_SUCCESS Then
cairo_destroy(c)
cairo_surface_destroy(surface)
End 1
End If
Sleep
'' Clean up the cairo context
cairo_destroy(c)
cairo_surface_destroy(surface)
'' end of cairo.bas
last reviewed: MrSwiss, 2018-05-05 -- changed: SizeOf(Integer) to SizeOf(ULong) reason: 32/64 compatibility