[error] LibCairo::Rectangle compiling demo

[nodrygo]

hello
first of all thank for this great work

trying the sample gtk_sample.cr I got this error

crystal run samples/gtk_sample.cr 
Showing last frame. Use --error-trace for full trace.
In src/lib_cairo.cr:20:18
 20 | rectangles : LibCairo::Rectangle*
                   ^------------------
Error: undefined constant LibCairo::Rectangle

please note that crystal-gobject (another great work) samples work on my machine

is it a problem with my cairo release ?
my env. is

Linux Mint19  5.3.0-40-generic #32~18.04.1-Ubuntu SMP
libgtk 3.22.30 (standard installed)
libcairo, libcairo-gobject2   1.15.10

thanks for help

[nodrygo]

resolved
simply adding this in src/lib_cairo.cr make things works correctly

  struct Rectangle
    x: Float64
    y: Float64
    width: Float64
    height: Float64
  end

[viachpaliy]

Hey, sorry this took me so long to look at, but to be honest it also mixes a couple of things so it's a bit harder to look at.
When I run gtk_sample.cr in Ubuntu, crystal-gobject use gir1.2-freedesktop for create cairo bindings in runtime.
This bindings consists from lib LibCairo and module Cairo. LibCairo wraps "raw" C struct (for example LibCairo::Rectangle).
module Cairo includes wrappers-classes for these struct : Context,Device etc.
In my opinion, you need install gir1.2-freedesktop package.

[CNFloss]

Hi I have installed gir1.2-freedesktop package in Ubuntu 18.04.4

I still receive the error above, do I have do any thing else besides install and update, to create cairo bindings in runtime?

thank you for your help.

[viachpaliy]

I have installed XUbuntu 19.10
You can check whether "compile-time" bindings run *samples/save_binding.cr *.
Bindings will saved in samples/cairo_binding.cr.
This is bindings from my computer:

@[Link("cairo-gobject")]
lib LibCairo

###########################################

Structs

###########################################

struct Context # struct
_data : UInt8[0]
end

struct Device # struct
_data : UInt8[0]
end

struct Surface # struct
_data : UInt8[0]
end

struct Matrix # struct
_data : UInt8[0]
end

struct Pattern # struct
_data : UInt8[0]
end

struct Region # struct
_data : UInt8[0]
end

struct FontOptions # struct
_data : UInt8[0]
end

struct FontFace # struct
_data : UInt8[0]
end

struct ScaledFont # struct
_data : UInt8[0]
end

struct Path # struct
_data : UInt8[0]
end

struct Rectangle # struct
x : Float64
y : Float64
width : Float64
height : Float64
end

struct RectangleInt # struct
x : Int32
y : Int32
width : Int32
height : Int32
end

###########################################

Enums

###########################################

alias Status = UInt32

alias Content = UInt32

alias Operator = UInt32

alias Antialias = UInt32

alias FillRule = UInt32

alias LineCap = UInt32

alias LineJoin = UInt32

alias TextClusterFlags = UInt32

alias FontSlant = UInt32

alias FontWeight = UInt32

alias SubpixelOrder = UInt32

alias HintStyle = UInt32

alias HintMetrics = UInt32

alias FontType = UInt32

alias PathDataType = UInt32

alias DeviceType = Int32

alias SurfaceType = UInt32

alias Format = Int32

alias PatternType = UInt32

alias Extend = UInt32

alias Filter = UInt32

alias RegionOverlap = UInt32

###########################################

Functions

###########################################

fun image_surface_create = cairo_image_surface_create() : Void
end

#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib",1,1
module Cairo#loc:pop
def self.image_surface_create
LibCairo.image_surface_create
nil
end

#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Context",1,1
class Context
include GObject::WrappedType

@pointer : Void*
def initialize(pointer : LibCairo::Context*)
  @pointer = pointer.as(Void*)
end

def to_unsafe
  @pointer.not_nil!.as(LibCairo::Context*)
end

end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Device",1,1
class Device
include GObject::WrappedType

@pointer : Void*
def initialize(pointer : LibCairo::Device*)
  @pointer = pointer.as(Void*)
end

def to_unsafe
  @pointer.not_nil!.as(LibCairo::Device*)
end

end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Surface",1,1
class Surface
include GObject::WrappedType

@pointer : Void*
def initialize(pointer : LibCairo::Surface*)
  @pointer = pointer.as(Void*)
end

def to_unsafe
  @pointer.not_nil!.as(LibCairo::Surface*)
end

end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Matrix",1,1
class Matrix
include GObject::WrappedType

@pointer : Void*
def initialize(pointer : LibCairo::Matrix*)
  @pointer = pointer.as(Void*)
end

def to_unsafe
  @pointer.not_nil!.as(LibCairo::Matrix*)
end

end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Pattern",1,1
class Pattern
include GObject::WrappedType

@pointer : Void*
def initialize(pointer : LibCairo::Pattern*)
  @pointer = pointer.as(Void*)
end

def to_unsafe
  @pointer.not_nil!.as(LibCairo::Pattern*)
end

end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Region",1,1
class Region
include GObject::WrappedType

@pointer : Void*
def initialize(pointer : LibCairo::Region*)
  @pointer = pointer.as(Void*)
end

def to_unsafe
  @pointer.not_nil!.as(LibCairo::Region*)
end

end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Status",1,1
enum Status : UInt32
ZERO_NONE = 0
SUCCESS = 0
NO_MEMORY = 1
INVALID_RESTORE = 2
INVALID_POP_GROUP = 3
NO_CURRENT_POINT = 4
INVALID_MATRIX = 5
INVALID_STATUS = 6
NULL_POINTER = 7
INVALID_STRING = 8
INVALID_PATH_DATA = 9
READ_ERROR = 10
WRITE_ERROR = 11
SURFACE_FINISHED = 12
SURFACE_TYPE_MISMATCH = 13
PATTERN_TYPE_MISMATCH = 14
INVALID_CONTENT = 15
INVALID_FORMAT = 16
INVALID_VISUAL = 17
FILE_NOT_FOUND = 18
INVALID_DASH = 19
INVALID_DSC_COMMENT = 20
INVALID_INDEX = 21
CLIP_NOT_REPRESENTABLE = 22
TEMP_FILE_ERROR = 23
INVALID_STRIDE = 24
FONT_TYPE_MISMATCH = 25
USER_FONT_IMMUTABLE = 26
USER_FONT_ERROR = 27
NEGATIVE_COUNT = 28
INVALID_CLUSTERS = 29
INVALID_SLANT = 30
INVALID_WEIGHT = 31
INVALID_SIZE = 32
USER_FONT_NOT_IMPLEMENTED = 33
DEVICE_TYPE_MISMATCH = 34
DEVICE_ERROR = 35
INVALID_MESH_CONSTRUCTION = 36
DEVICE_FINISHED = 37
JBIG2_GLOBAL_MISSING = 38
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Content",1,1
enum Content : UInt32
ZERO_NONE = 0
COLOR = 4096
ALPHA = 8192
COLOR_ALPHA = 12288
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Operator",1,1
enum Operator : UInt32
ZERO_NONE = 0
CLEAR = 0
SOURCE = 1
OVER = 2
IN = 3
OUT = 4
ATOP = 5
DEST = 6
DEST_OVER = 7
DEST_IN = 8
DEST_OUT = 9
DEST_ATOP = 10
XOR = 11
ADD = 12
SATURATE = 13
MULTIPLY = 14
SCREEN = 15
OVERLAY = 16
DARKEN = 17
LIGHTEN = 18
COLOR_DODGE = 19
COLOR_BURN = 20
HARD_LIGHT = 21
SOFT_LIGHT = 22
DIFFERENCE = 23
EXCLUSION = 24
HSL_HUE = 25
HSL_SATURATION = 26
HSL_COLOR = 27
HSL_LUMINOSITY = 28
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/Antialias",1,1
enum Antialias : UInt32
ZERO_NONE = 0
DEFAULT = 0
NONE = 1
GRAY = 2
SUBPIXEL = 3
FAST = 4
GOOD = 5
BEST = 6
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/FillRule",1,1
enum FillRule : UInt32
ZERO_NONE = 0
WINDING = 0
EVEN_ODD = 1
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/LineCap",1,1
enum LineCap : UInt32
ZERO_NONE = 0
BUTT = 0
ROUND = 1
SQUARE = 2
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/LineJoin",1,1
enum LineJoin : UInt32
ZERO_NONE = 0
MITER = 0
ROUND = 1
BEVEL = 2
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/TextClusterFlags",1,1
enum TextClusterFlags : UInt32
ZERO_NONE = 0
BACKWARD = 1
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/FontSlant",1,1
enum FontSlant : UInt32
ZERO_NONE = 0
NORMAL = 0
ITALIC = 1
OBLIQUE = 2
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/FontWeight",1,1
enum FontWeight : UInt32
ZERO_NONE = 0
NORMAL = 0
BOLD = 1
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/SubpixelOrder",1,1
enum SubpixelOrder : UInt32
ZERO_NONE = 0
DEFAULT = 0
RGB = 1
BGR = 2
VRGB = 3
VBGR = 4
end
#loc:pop
#loc:push#loc:"/usr/lib/x86_64-linux-gnu/girepository-1.0/cairo-1.0.typelib/HintStyle",1,1
enum HintStyle : UInt32
ZERO_NONE = 0
DEFAULT = 0
NONE = 1
SLIGHT = 2
MEDIUM = 3
FULL = 4
end
#loc:pop

[viachpaliy]

In my opinion, matter in different version "gir1.2-freedesktop" package for different version of Ubuntu.
I added commented Rectangle structure definition in src/lib_cairo.cr file.
Uncomment its definition (lines 7...12).