Sets our main struct and passes it to the parent class
Append the path onto the current path. The path may be either the return value from one of cairo_copy_path() or cairo_copy_path_flat() or it may be constructed manually. See cairo_path_t for details on how the path data structure should be initialized, and note that path->status must be initialized to CAIRO_STATUS_SUCCESS. Since 1.0
Adds a circular arc of the given radius to the current path. The arc is centered at (xc, yc), begins at angle1 and proceeds in the direction of increasing angles to end at angle2. If angle2 is less than angle1 it will be progressively increased by 2*M_PI until it is greater than angle1. If there is a current point, an initial line segment will be added to the path to connect the current point to the beginning of the arc. If this initial line is undesired, it can be avoided by calling cairo_new_sub_path() before calling cairo_arc(). Angles are measured in radians. An angle of 0.0 is in the direction of the positive X axis (in user space). An angle of M_PI/2.0 radians (90 degrees) is in the direction of the positive Y axis (in user space). Angles increase in the direction from the positive X axis toward the positive Y axis. So with the default transformation matrix, angles increase in a clockwise direction. (To convert from degrees to radians, use degrees * (M_PI / 180.).) This function gives the arc in the direction of increasing angles; see cairo_arc_negative() to get the arc in the direction of decreasing angles. The arc is circular in user space. To achieve an elliptical arc, you can scale the current transformation matrix by different amounts in the X and Y directions. For example, to draw an ellipse Since 1.0
Adds a circular arc of the given radius to the current path. The arc is centered at (xc, yc), begins at angle1 and proceeds in the direction of decreasing angles to end at angle2. If angle2 is greater than angle1 it will be progressively decreased by 2*M_PI until it is less than angle1. See cairo_arc() for more details. This function differs only in the direction of the arc between the two angles. Since 1.0
Establishes a new clip region by intersecting the current clip region with the current path as it would be filled by cairo_fill() and according to the current fill rule (see cairo_set_fill_rule()). After cairo_clip(), the current path will be cleared from the cairo context. The current clip region affects all drawing operations by effectively masking out any changes to the surface that are outside the current clip region. Calling cairo_clip() can only make the clip region smaller, never larger. But the current clip is part of the graphics state, so a temporary restriction of the clip region can be achieved by calling cairo_clip() within a cairo_save()/cairo_restore() pair. The only other means of increasing the size of the clip region is cairo_reset_clip(). Since 1.0
Computes a bounding box in user coordinates covering the area inside the current clip. Since 1.4
Establishes a new clip region by intersecting the current clip region with the current path as it would be filled by cairo_fill() and according to the current fill rule (see cairo_set_fill_rule()). Unlike cairo_clip(), cairo_clip_preserve() preserves the path within the cairo context. The current clip region affects all drawing operations by effectively masking out any changes to the surface that are outside the current clip region. Calling cairo_clip_preserve() can only make the clip region smaller, never larger. But the current clip is part of the graphics state, so a temporary restriction of the clip region can be achieved by calling cairo_clip_preserve() within a cairo_save()/cairo_restore() pair. The only other means of increasing the size of the clip region is cairo_reset_clip(). Since 1.0
Adds a line segment to the path from the current point to the beginning of the current sub-path, (the most recent point passed to cairo_move_to()), and closes this sub-path. After this call the current point will be at the joined endpoint of the sub-path. The behavior of cairo_close_path() is distinct from simply calling cairo_line_to() with the equivalent coordinate in the case of stroking. When a closed sub-path is stroked, there are no caps on the ends of the sub-path. Instead, there is a line join connecting the final and initial segments of the sub-path. If there is no current point before the call to cairo_close_path(), this function will have no effect. Note: As of cairo version 1.2.4 any call to cairo_close_path() will place an explicit MOVE_TO element into the path immediately after the CLOSE_PATH element, (which can be seen in cairo_copy_path() for example). This can simplify path processing in some cases as it may not be necessary to save the "last move_to point" during processing as the MOVE_TO immediately after the CLOSE_PATH will provide that point. Since 1.0
Gets the current clip region as a list of rectangles in user coordinates. Never returns NULL. The status in the list may be CAIRO_STATUS_CLIP_NOT_REPRESENTABLE to indicate that the clip region cannot be represented as a list of user-space rectangles. The status may have other values to indicate other errors. Since 1.4
Emits the current page for backends that support multiple pages, but doesn't clear it, so, the contents of the current page will be retained for the next page too. Use cairo_show_page() if you want to get an empty page after the emission. This is a convenience function that simply calls cairo_surface_copy_page() on cr's target. Since 1.0
Creates a copy of the current path and returns it to the user as a cairo_path_t. See cairo_path_data_t for hints on how to iterate over the returned data structure. This function will always return a valid pointer, but the result will have no data (data==NULL and num_data==0), if either of the following Since 1.0
Gets a flattened copy of the current path and returns it to the user as a cairo_path_t. See cairo_path_data_t for hints on how to iterate over the returned data structure. This function is like cairo_copy_path() except that any curves in the path will be approximated with piecewise-linear approximations, (accurate to within the current tolerance value). That is, the result is guaranteed to not have any elements of type CAIRO_PATH_CURVE_TO which will instead be replaced by a series of CAIRO_PATH_LINE_TO elements. This function will always return a valid pointer, but the result will have no data (data==NULL and num_data==0), if either of the following Since 1.0
Adds a cubic Bézier spline to the path from the current point to position (x3, y3) in user-space coordinates, using (x1, y1) and (x2, y2) as the control points. After this call the current point will be (x3, y3). If there is no current point before the call to cairo_curve_to() this function will behave as if preceded by a call to cairo_move_to(cr, x1, y1). Since 1.0
Decreases the reference count on cr by one. If the result is zero, then cr and all associated resources are freed. See cairo_reference().
Transform a coordinate from device space to user space by multiplying the given point by the inverse of the current transformation matrix (CTM). Since 1.0
Transform a distance vector from device space to user space. This function is similar to cairo_device_to_user() except that the translation components of the inverse CTM will be ignored when transforming (dx,dy). Since 1.0
A drawing operator that fills the current path according to the current fill rule, (each sub-path is implicitly closed before being filled). After cairo_fill(), the current path will be cleared from the cairo context. See cairo_set_fill_rule() and cairo_fill_preserve(). Since 1.0
Computes a bounding box in user coordinates covering the area that would be affected, (the "inked" area), by a cairo_fill() operation given the current path and fill parameters. If the current path is empty, returns an empty rectangle ((0,0), (0,0)). Surface dimensions and clipping are not taken into account. Contrast with cairo_path_extents(), which is similar, but returns non-zero extents for some paths with no inked area, (such as a simple line segment). Note that cairo_fill_extents() must necessarily do more work to compute the precise inked areas in light of the fill rule, so cairo_path_extents() may be more desirable for sake of performance if the non-inked path extents are desired. See cairo_fill(), cairo_set_fill_rule() and cairo_fill_preserve(). Since 1.0
A drawing operator that fills the current path according to the current fill rule, (each sub-path is implicitly closed before being filled). Unlike cairo_fill(), cairo_fill_preserve() preserves the path within the cairo context. See cairo_set_fill_rule() and cairo_fill(). Since 1.0
Gets the font extents for the currently selected font. Since 1.0
Gets the current shape antialiasing mode, as set by cairo_set_antialias(). Since 1.0
Gets the current point of the current path, which is conceptually the final point reached by the path so far. The current point is returned in the user-space coordinate system. If there is no defined current point or if cr is in an error status, x and y will both be set to 0.0. It is possible to check this in advance with cairo_has_current_point(). Most path construction functions alter the current point. See the Since 1.0
Gets the current dash array. If not NULL, dashes should be big enough to hold at least the number of values returned by cairo_get_dash_count(). Since 1.4
This function returns the length of the dash array in cr (0 if dashing is not currently in effect). See also cairo_set_dash() and cairo_get_dash(). Since 1.4
Gets the current fill rule, as set by cairo_set_fill_rule(). Since 1.0
Gets the current font face for a cairo_t. Since 1.0
Stores the current font matrix into matrix. See cairo_set_font_matrix(). Since 1.0
Retrieves font rendering options set via cairo_set_font_options. Note that the returned options do not include any options derived from the underlying surface; they are literally the options passed to cairo_set_font_options(). Since 1.0
Gets the current destination surface for the context. This is either the original target surface as passed to cairo_create() or the target surface for the current group as started by the most recent call to cairo_push_group() or cairo_push_group_with_content(). This function will always return a valid pointer, but the result can be a "nil" surface if cr is already in an error state, (ie. cairo_status() != CAIRO_STATUS_SUCCESS). A nil surface is indicated by cairo_surface_status() != CAIRO_STATUS_SUCCESS. Since 1.2
Gets the current line cap style, as set by cairo_set_line_cap(). Since 1.0
Gets the current line join style, as set by cairo_set_line_join(). Since 1.0
This function returns the current line width value exactly as set by cairo_set_line_width(). Note that the value is unchanged even if the CTM has changed between the calls to cairo_set_line_width() and cairo_get_line_width(). Since 1.0
Stores the current transformation matrix (CTM) into matrix. Since 1.0
Gets the current miter limit, as set by cairo_set_miter_limit(). Since 1.0
Gets the current compositing operator for a cairo context. Since 1.0
Returns the current reference count of cr. Since 1.4
Gets the current scaled font for a cairo_t. Since 1.4
Gets the current source pattern for cr. Since 1.0
the main Gtk struct as a void*
Gets the target surface for the cairo context as passed to cairo_create(). This function will always return a valid pointer, but the result can be a "nil" surface if cr is already in an error state, (ie. cairo_status() != CAIRO_STATUS_SUCCESS). A nil surface is indicated by cairo_surface_status() != CAIRO_STATUS_SUCCESS. Since 1.0
Gets the current tolerance value, as set by cairo_set_tolerance(). Since 1.0
Return user data previously attached to cr using the specified key. If no user data has been attached with the given key this function returns NULL. Since 1.4
Gets the extents for an array of glyphs. The extents describe a user-space rectangle that encloses the "inked" portion of the glyphs, (as they would be drawn by cairo_show_glyphs()). Additionally, the x_advance and y_advance values indicate the amount by which the current point would be advanced by cairo_show_glyphs(). Note that whitespace glyphs do not contribute to the size of the rectangle (extents.width and extents.height). Since 1.0
Adds closed paths for the glyphs to the current path. The generated path if filled, achieves an effect similar to that of cairo_show_glyphs(). Since 1.0
Returns whether a current point is defined on the current path. See cairo_get_current_point() for details on the current point. Since 1.6
Resets the current transformation matrix (CTM) by setting it equal to the identity matrix. That is, the user-space and device-space axes will be aligned and one user-space unit will transform to one device-space unit. Since 1.0
Tests whether the given point is inside the area that would be visible through the current clip, i.e. the area that would be filled by a cairo_paint() operation. See cairo_clip(), and cairo_clip_preserve(). Since 1.10
Tests whether the given point is inside the area that would be affected by a cairo_fill() operation given the current path and filling parameters. Surface dimensions and clipping are not taken into account. See cairo_fill(), cairo_set_fill_rule() and cairo_fill_preserve(). Since 1.0
Tests whether the given point is inside the area that would be affected by a cairo_stroke() operation given the current path and stroking parameters. Surface dimensions and clipping are not taken into account. See cairo_stroke(), cairo_set_line_width(), cairo_set_line_join(), cairo_set_line_cap(), cairo_set_dash(), and cairo_stroke_preserve(). Since 1.0
Adds a line to the path from the current point to position (x, y) in user-space coordinates. After this call the current point will be (x, y). If there is no current point before the call to cairo_line_to() this function will behave as cairo_move_to(cr, x, y). Since 1.0
A drawing operator that paints the current source using the alpha channel of pattern as a mask. (Opaque areas of pattern are painted with the source, transparent areas are not painted.) Since 1.0
A drawing operator that paints the current source using the alpha channel of surface as a mask. (Opaque areas of surface are painted with the source, transparent areas are not painted.) Since 1.0
Begin a new sub-path. After this call the current point will be (x, y). Since 1.0
Clears the current path. After this call there will be no path and no current point. Since 1.0
Begin a new sub-path. Note that the existing path is not affected. After this call there will be no current point. In many cases, this call is not needed since new sub-paths are frequently started with cairo_move_to(). A call to cairo_new_sub_path() is particularly useful when beginning a new sub-path with one of the cairo_arc() calls. This makes things easier as it is no longer necessary to manually compute the arc's initial coordinates for a call to cairo_move_to(). Since 1.2
A drawing operator that paints the current source everywhere within the current clip region. Since 1.0
A drawing operator that paints the current source everywhere within the current clip region using a mask of constant alpha value alpha. The effect is similar to cairo_paint(), but the drawing is faded out using the alpha value. Since 1.0
Computes a bounding box in user-space coordinates covering the points on the current path. If the current path is empty, returns an empty rectangle ((0,0), (0,0)). Stroke parameters, fill rule, surface dimensions and clipping are not taken into account. Contrast with cairo_fill_extents() and cairo_stroke_extents() which return the extents of only the area that would be "inked" by the corresponding drawing operations. The result of cairo_path_extents() is defined as equivalent to the limit of cairo_stroke_extents() with CAIRO_LINE_CAP_ROUND as the line width approaches 0.0, (but never reaching the empty-rectangle returned by cairo_stroke_extents() for a line width of 0.0). Specifically, this means that zero-area sub-paths such as cairo_move_to();cairo_line_to() segments, (even degenerate cases where the coordinates to both calls are identical), will be considered as contributing to the extents. However, a lone cairo_move_to() will not contribute to the results of cairo_path_extents(). Since 1.6
Terminates the redirection begun by a call to cairo_push_group() or cairo_push_group_with_content() and returns a new pattern containing the results of all drawing operations performed to the group. The cairo_pop_group() function calls cairo_restore(), (balancing a call to cairo_save() by the push_group function), so that any changes to the graphics state will not be visible outside the group. Since 1.2
Terminates the redirection begun by a call to cairo_push_group() or cairo_push_group_with_content() and installs the resulting pattern as the source pattern in the given cairo context. The behavior of this function is equivalent to the sequence of Since 1.2
Temporarily redirects drawing to an intermediate surface known as a group. The redirection lasts until the group is completed by a call to cairo_pop_group() or cairo_pop_group_to_source(). These calls provide the result of any drawing to the group as a pattern, (either as an explicit object, or set as the source pattern). This group functionality can be convenient for performing intermediate compositing. One common use of a group is to render objects as opaque within the group, (so that they occlude each other), and then blend the result with translucence onto the destination. Groups can be nested arbitrarily deep by making balanced calls to cairo_push_group()/cairo_pop_group(). Each call pushes/pops the new target group onto/from a stack. The cairo_push_group() function calls cairo_save() so that any changes to the graphics state will not be visible outside the group, (the pop_group functions call cairo_restore()). By default the intermediate group will have a content type of CAIRO_CONTENT_COLOR_ALPHA. Other content types can be chosen for the group by using cairo_push_group_with_content() instead. As an example, here is how one might fill and stroke a path with translucence, but without any portion of the fill being visible Since 1.2
Temporarily redirects drawing to an intermediate surface known as a group. The redirection lasts until the group is completed by a call to cairo_pop_group() or cairo_pop_group_to_source(). These calls provide the result of any drawing to the group as a pattern, (either as an explicit object, or set as the source pattern). The group will have a content type of content. The ability to control this content type is the only distinction between this function and cairo_push_group() which you should see for a more detailed description of group rendering. Since 1.2
Adds a closed sub-path rectangle of the given size to the current path at position (x, y) in user-space coordinates. Since 1.0
Increases the reference count on cr by one. This prevents cr from being destroyed until a matching call to cairo_destroy() is made. The number of references to a cairo_t can be get using cairo_get_reference_count(). Since 1.0
Relative-coordinate version of cairo_curve_to(). All offsets are relative to the current point. Adds a cubic Bézier spline to the path from the current point to a point offset from the current point by (dx3, dy3), using points offset by (dx1, dy1) and (dx2, dy2) as the control points. After this call the current point will be offset by (dx3, dy3). Given a current point of (x, y), cairo_rel_curve_to(cr, dx1, dy1, dx2, dy2, dx3, dy3) is logically equivalent to cairo_curve_to(cr, x+dx1, y+dy1, x+dx2, y+dy2, x+dx3, y+dy3). It is an error to call this function with no current point. Doing so will cause cr to shutdown with a status of CAIRO_STATUS_NO_CURRENT_POINT. Since 1.0
Relative-coordinate version of cairo_line_to(). Adds a line to the path from the current point to a point that is offset from the current point by (dx, dy) in user space. After this call the current point will be offset by (dx, dy). Given a current point of (x, y), cairo_rel_line_to(cr, dx, dy) is logically equivalent to cairo_line_to(cr, x + dx, y + dy). It is an error to call this function with no current point. Doing so will cause cr to shutdown with a status of CAIRO_STATUS_NO_CURRENT_POINT. Since 1.0
Begin a new sub-path. After this call the current point will offset by (x, y). Given a current point of (x, y), cairo_rel_move_to(cr, dx, dy) is logically equivalent to cairo_move_to(cr, x + dx, y + dy). It is an error to call this function with no current point. Doing so will cause cr to shutdown with a status of CAIRO_STATUS_NO_CURRENT_POINT. Since 1.0
Reset the current clip region to its original, unrestricted state. That is, set the clip region to an infinitely large shape containing the target surface. Equivalently, if infinity is too hard to grasp, one can imagine the clip region being reset to the exact bounds of the target surface. Note that code meant to be reusable should not call cairo_reset_clip() as it will cause results unexpected by higher-level code which calls cairo_clip(). Consider using cairo_save() and cairo_restore() around cairo_clip() as a more robust means of temporarily restricting the clip region. Since 1.0
Restores cr to the state saved by a preceding call to cairo_save() and removes that state from the stack of saved states. Since 1.0
Modifies the current transformation matrix (CTM) by rotating the user-space axes by angle radians. The rotation of the axes takes places after any existing transformation of user space. The rotation direction for positive angles is from the positive X axis toward the positive Y axis. Since 1.0
Makes a copy of the current state of cr and saves it on an internal stack of saved states for cr. When cairo_restore() is called, cr will be restored to the saved state. Multiple calls to cairo_save() and cairo_restore() can be nested; each call to cairo_restore() restores the state from the matching paired cairo_save(). It isn't necessary to clear all saved states before a cairo_t is freed. If the reference count of a cairo_t drops to zero in response to a call to cairo_destroy(), any saved states will be freed along with the cairo_t. Since 1.0
Modifies the current transformation matrix (CTM) by scaling the X and Y user-space axes by sx and sy respectively. The scaling of the axes takes place after any existing transformation of user space. Since 1.0
Note: The cairo_select_font_face() function call is part of what the cairo designers call the "toy" text API. It is convenient for short demos and simple programs, but it is not expected to be adequate for serious text-using applications. Selects a family and style of font from a simplified description as a family name, slant and weight. Cairo provides no operation to list available family names on the system (this is a "toy", remember), but the standard CSS2 generic family names, ("serif", "sans-serif", "cursive", "fantasy", "monospace"), are likely to work as expected. If family starts with the string "cairo:", or if no native font backends are compiled in, cairo will use an internal font family. The internal font family recognizes many modifiers in the family string, most notably, it recognizes the string "monospace". That is, the family name "cairo:monospace" will use the monospace version of the internal font family. For "real" font selection, see the font-backend-specific font_face_create functions for the font backend you are using. (For example, if you are using the freetype-based cairo-ft font backend, see cairo_ft_font_face_create_for_ft_face() or cairo_ft_font_face_create_for_pattern().) The resulting font face could then be used with cairo_scaled_font_create() and cairo_set_scaled_font(). Similarly, when using the "real" font support, you can call directly into the underlying font system, (such as fontconfig or freetype), for operations such as listing available fonts, etc. It is expected that most applications will need to use a more comprehensive font handling and text layout library, (for example, pango), in conjunction with cairo. If text is drawn without a call to cairo_select_font_face(), (nor cairo_set_font_face() nor cairo_set_scaled_font()), the default family is platform-specific, but is essentially "sans-serif". Default slant is CAIRO_FONT_SLANT_NORMAL, and default weight is CAIRO_FONT_WEIGHT_NORMAL. This function is equivalent to a call to cairo_toy_font_face_create() followed by cairo_set_font_face(). Since 1.0
Set the antialiasing mode of the rasterizer used for drawing shapes. This value is a hint, and a particular backend may or may not support a particular value. At the current time, no backend supports CAIRO_ANTIALIAS_SUBPIXEL when drawing shapes. Note that this option does not affect text rendering, instead see cairo_font_options_set_antialias(). Since 1.0
Sets the dash pattern to be used by cairo_stroke(). A dash pattern is specified by dashes, an array of positive values. Each value provides the length of alternate "on" and "off" portions of the stroke. The offset specifies an offset into the pattern at which the stroke begins. Each "on" segment will have caps applied as if the segment were a separate sub-path. In particular, it is valid to use an "on" length of 0.0 with CAIRO_LINE_CAP_ROUND or CAIRO_LINE_CAP_SQUARE in order to distributed dots or squares along a path. Note: The length values are in user-space units as evaluated at the time of stroking. This is not necessarily the same as the user space at the time of cairo_set_dash(). If num_dashes is 0 dashing is disabled. If num_dashes is 1 a symmetric pattern is assumed with alternating on and off portions of the size specified by the single value in dashes. If any value in dashes is negative, or if all values are 0, then cr will be put into an error state with a status of CAIRO_STATUS_INVALID_DASH. Since 1.0
Set the current fill rule within the cairo context. The fill rule is used to determine which regions are inside or outside a complex (potentially self-intersecting) path. The current fill rule affects both cairo_fill() and cairo_clip(). See cairo_fill_rule_t for details on the semantics of each available fill rule. The default fill rule is CAIRO_FILL_RULE_WINDING. Since 1.0
Replaces the current cairo_font_face_t object in the cairo_t with font_face. The replaced font face in the cairo_t will be destroyed if there are no other references to it. Since 1.0
Sets the current font matrix to matrix. The font matrix gives a transformation from the design space of the font (in this space, the em-square is 1 unit by 1 unit) to user space. Normally, a simple scale is used (see cairo_set_font_size()), but a more complex font matrix can be used to shear the font or stretch it unequally along the two axes Since 1.0
Sets a set of custom font rendering options for the cairo_t. Rendering options are derived by merging these options with the options derived from underlying surface; if the value in options has a default value (like CAIRO_ANTIALIAS_DEFAULT), then the value from the surface is used. Since 1.0
Sets the current font matrix to a scale by a factor of size, replacing any font matrix previously set with cairo_set_font_size() or cairo_set_font_matrix(). This results in a font size of size user space units. (More precisely, this matrix will result in the font's em-square being a size by size square in user space.) If text is drawn without a call to cairo_set_font_size(), (nor cairo_set_font_matrix() nor cairo_set_scaled_font()), the default font size is 10.0. Since 1.0
Sets the current line cap style within the cairo context. See cairo_line_cap_t for details about how the available line cap styles are drawn. As with the other stroke parameters, the current line cap style is examined by cairo_stroke(), cairo_stroke_extents(), and cairo_stroke_to_path(), but does not have any effect during path construction. The default line cap style is CAIRO_LINE_CAP_BUTT. Since 1.0
Sets the current line join style within the cairo context. See cairo_line_join_t for details about how the available line join styles are drawn. As with the other stroke parameters, the current line join style is examined by cairo_stroke(), cairo_stroke_extents(), and cairo_stroke_to_path(), but does not have any effect during path construction. The default line join style is CAIRO_LINE_JOIN_MITER. Since 1.0
Sets the current line width within the cairo context. The line width value specifies the diameter of a pen that is circular in user space, (though device-space pen may be an ellipse in general due to scaling/shear/rotation of the CTM). Note: When the description above refers to user space and CTM it refers to the user space and CTM in effect at the time of the stroking operation, not the user space and CTM in effect at the time of the call to cairo_set_line_width(). The simplest usage makes both of these spaces identical. That is, if there is no change to the CTM between a call to cairo_set_line_width() and the stroking operation, then one can just pass user-space values to cairo_set_line_width() and ignore this note. As with the other stroke parameters, the current line width is examined by cairo_stroke(), cairo_stroke_extents(), and cairo_stroke_to_path(), but does not have any effect during path construction. The default line width value is 2.0. Since 1.0
Modifies the current transformation matrix (CTM) by setting it equal to matrix. Since 1.0
Sets the current miter limit within the cairo context. If the current line join style is set to CAIRO_LINE_JOIN_MITER (see cairo_set_line_join()), the miter limit is used to determine whether the lines should be joined with a bevel instead of a miter. Cairo divides the length of the miter by the line width. If the result is greater than the miter limit, the style is converted to a bevel. As with the other stroke parameters, the current line miter limit is examined by cairo_stroke(), cairo_stroke_extents(), and cairo_stroke_to_path(), but does not have any effect during path construction. The default miter limit value is 10.0, which will convert joins with interior angles less than 11 degrees to bevels instead of miters. For reference, a miter limit of 2.0 makes the miter cutoff at 60 degrees, and a miter limit of 1.414 makes the cutoff at 90 degrees. A miter limit for a desired angle can be computed as: miter limit = 1/sin(angle/2) Since 1.0
Sets the compositing operator to be used for all drawing operations. See cairo_operator_t for details on the semantics of each available compositing operator. The default operator is CAIRO_OPERATOR_OVER. Since 1.0
Replaces the current font face, font matrix, and font options in the cairo_t with those of the cairo_scaled_font_t. Except for some translation, the current CTM of the cairo_t should be the same as that of the cairo_scaled_font_t, which can be accessed using cairo_scaled_font_get_ctm(). Since 1.2
Sets the source pattern within cr to source. This pattern will then be used for any subsequent drawing operation until a new source pattern is set. Note: The pattern's transformation matrix will be locked to the user space in effect at the time of cairo_set_source(). This means that further modifications of the current transformation matrix will not affect the source pattern. See cairo_pattern_set_matrix(). The default source pattern is a solid pattern that is opaque black, (that is, it is equivalent to cairo_set_source_rgb(cr, 0.0, 0.0, 0.0)). Since 1.0
Sets the source pattern within cr to an opaque color. This opaque color will then be used for any subsequent drawing operation until a new source pattern is set. The color components are floating point numbers in the range 0 to 1. If the values passed in are outside that range, they will be clamped. The default source pattern is opaque black, (that is, it is equivalent to cairo_set_source_rgb(cr, 0.0, 0.0, 0.0)). Since 1.0
Sets the source pattern within cr to a translucent color. This color will then be used for any subsequent drawing operation until a new source pattern is set. The color and alpha components are floating point numbers in the range 0 to 1. If the values passed in are outside that range, they will be clamped. The default source pattern is opaque black, (that is, it is equivalent to cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0)). Since 1.0
This is a convenience function for creating a pattern from surface and setting it as the source in cr with cairo_set_source(). The x and y parameters give the user-space coordinate at which the surface origin should appear. (The surface origin is its upper-left corner before any transformation has been applied.) The x and y parameters are negated and then set as translation values in the pattern matrix. Other than the initial translation pattern matrix, as described above, all other pattern attributes, (such as its extend mode), are set to the default values as in cairo_pattern_create_for_surface(). The resulting pattern can be queried with cairo_get_source() so that these attributes can be modified if desired, (eg. to create a repeating pattern with cairo_pattern_set_extend()). Since 1.0
Sets the tolerance used when converting paths into trapezoids. Curved segments of the path will be subdivided until the maximum deviation between the original path and the polygonal approximation is less than tolerance. The default value is 0.1. A larger value will give better performance, a smaller value, better appearance. (Reducing the value from the default value of 0.1 is unlikely to improve appearance significantly.) The accuracy of paths within Cairo is limited by the precision of its internal arithmetic, and the prescribed tolerance is restricted to the smallest representable internal value. Since 1.0
Attach user data to cr. To remove user data from a surface, call this function with the key that was used to set it and NULL for data. Since 1.4
A drawing operator that generates the shape from an array of glyphs, rendered according to the current font face, font size (font matrix), and font options. Since 1.0
Emits and clears the current page for backends that support multiple pages. Use cairo_copy_page() if you don't want to clear the page. This is a convenience function that simply calls cairo_surface_show_page() on cr's target. Since 1.0
A drawing operator that generates the shape from a string of UTF-8 characters, rendered according to the current font_face, font_size (font_matrix), and font_options. This function first computes a set of glyphs for the string of text. The first glyph is placed so that its origin is at the current point. The origin of each subsequent glyph is offset from that of the previous glyph by the advance values of the previous glyph. After this call the current point is moved to the origin of where the next glyph would be placed in this same progression. That is, the current point will be at the origin of the final glyph offset by its advance values. This allows for easy display of a single logical string with multiple calls to cairo_show_text(). Note: The cairo_show_text() function call is part of what the cairo designers call the "toy" text API. It is convenient for short demos and simple programs, but it is not expected to be adequate for serious text-using applications. See cairo_show_glyphs() for the "real" text display API in cairo. Since 1.0
This operation has rendering effects similar to cairo_show_glyphs() but, if the target surface supports it, uses the provided text and cluster mapping to embed the text for the glyphs shown in the output. If the target does not support the extended attributes, this function acts like the basic cairo_show_glyphs() as if it had been passed glyphs and num_glyphs. The mapping between utf8 and glyphs is provided by an array of clusters. Each cluster covers a number of text bytes and glyphs, and neighboring clusters cover neighboring areas of utf8 and glyphs. The clusters should collectively cover utf8 and glyphs in entirety. The first cluster always covers bytes from the beginning of utf8. If cluster_flags do not have the CAIRO_TEXT_CLUSTER_FLAG_BACKWARD set, the first cluster also covers the beginning of glyphs, otherwise it covers the end of the glyphs array and following clusters move backward. See cairo_text_cluster_t for constraints on valid clusters. Since 1.8
Checks whether an error has previously occurred for this context. Since 1.0
A drawing operator that strokes the current path according to the current line width, line join, line cap, and dash settings. After cairo_stroke(), the current path will be cleared from the cairo context. See cairo_set_line_width(), cairo_set_line_join(), cairo_set_line_cap(), cairo_set_dash(), and cairo_stroke_preserve(). Note: Degenerate segments and sub-paths are treated specially and provide a useful result. These can result in two different Since 1.0
Computes a bounding box in user coordinates covering the area that would be affected, (the "inked" area), by a cairo_stroke() operation given the current path and stroke parameters. If the current path is empty, returns an empty rectangle ((0,0), (0,0)). Surface dimensions and clipping are not taken into account. Note that if the line width is set to exactly zero, then cairo_stroke_extents() will return an empty rectangle. Contrast with cairo_path_extents() which can be used to compute the non-empty bounds as the line width approaches zero. Note that cairo_stroke_extents() must necessarily do more work to compute the precise inked areas in light of the stroke parameters, so cairo_path_extents() may be more desirable for sake of performance if non-inked path extents are desired. See cairo_stroke(), cairo_set_line_width(), cairo_set_line_join(), cairo_set_line_cap(), cairo_set_dash(), and cairo_stroke_preserve(). Since 1.0
A drawing operator that strokes the current path according to the current line width, line join, line cap, and dash settings. Unlike cairo_stroke(), cairo_stroke_preserve() preserves the path within the cairo context. See cairo_set_line_width(), cairo_set_line_join(), cairo_set_line_cap(), cairo_set_dash(), and cairo_stroke_preserve(). Since 1.0
Gets the extents for a string of text. The extents describe a user-space rectangle that encloses the "inked" portion of the text, (as it would be drawn by cairo_show_text()). Additionally, the x_advance and y_advance values indicate the amount by which the current point would be advanced by cairo_show_text(). Note that whitespace characters do not directly contribute to the size of the rectangle (extents.width and extents.height). They do contribute indirectly by changing the position of non-whitespace characters. In particular, trailing whitespace characters are likely to not affect the size of the rectangle, though they will affect the x_advance and y_advance values. Since 1.0
Adds closed paths for text to the current path. The generated path if filled, achieves an effect similar to that of cairo_show_text(). Text conversion and positioning is done similar to cairo_show_text(). Like cairo_show_text(), After this call the current point is moved to the origin of where the next glyph would be placed in this same progression. That is, the current point will be at the origin of the final glyph offset by its advance values. This allows for chaining multiple calls to to cairo_text_path() without having to set current point in between. Note: The cairo_text_path() function call is part of what the cairo designers call the "toy" text API. It is convenient for short demos and simple programs, but it is not expected to be adequate for serious text-using applications. See cairo_glyph_path() for the "real" text path API in cairo. Since 1.0
Modifies the current transformation matrix (CTM) by applying matrix as an additional transformation. The new transformation of user space takes place after any existing transformation. Since 1.0
Modifies the current transformation matrix (CTM) by translating the user-space origin by (tx, ty). This offset is interpreted as a user-space coordinate according to the CTM in place before the new call to cairo_translate(). In other words, the translation of the user-space origin takes place after any existing transformation. Since 1.0
Transform a coordinate from user space to device space by multiplying the given point by the current transformation matrix (CTM). Since 1.0
Transform a distance vector from user space to device space. This function is similar to cairo_user_to_device() except that the translation components of the CTM will be ignored when transforming (dx,dy). Since 1.0
Creates a new context with all graphics state parameters set to default values and with target as a target surface.
Allocates an array of cairo_glyph_t's. This function is only useful in implementations of cairo_user_scaled_font_text_to_glyphs_func_t where the user needs to allocate an array of glyphs that cairo will free. For all other uses, user can use their own allocation method for glyphs. This function returns NULL if num_glyphs is not positive, or if out of memory. That means, the NULL return value signals out-of-memory only if num_glyphs was positive. Since 1.8
Frees an array of cairo_glyph_t's allocated using cairo_glyph_allocate(). This function is only useful to free glyph array returned by cairo_scaled_font_text_to_glyphs() where cairo returns an array of glyphs that the user will free. For all other uses, user can use their own allocation method for glyphs. Since 1.8
Immediately releases all memory associated with path. After a call to cairo_path_destroy() the path pointer is no longer valid and should not be used further. Note: cairo_path_destroy() should only be called with a pointer to a cairo_path_t returned by a cairo function. Any path that is created manually (ie. outside of cairo) should be destroyed manually as well. Since 1.0
Unconditionally frees rectangle_list and all associated references. After this call, the rectangle_list pointer must not be dereferenced. Since 1.4
Allocates an array of cairo_text_cluster_t's. This function is only useful in implementations of cairo_user_scaled_font_text_to_glyphs_func_t where the user needs to allocate an array of text clusters that cairo will free. For all other uses, user can use their own allocation method for text clusters. This function returns NULL if num_clusters is not positive, or if out of memory. That means, the NULL return value signals out-of-memory only if num_clusters was positive. Since 1.8
Frees an array of cairo_text_cluster's allocated using cairo_text_cluster_allocate(). This function is only useful to free text cluster array returned by cairo_scaled_font_text_to_glyphs() where cairo returns an array of text clusters that the user will free. For all other uses, user can use their own allocation method for text clusters. Since 1.8
Creates a font face from a triplet of family, slant, and weight. These font faces are used in implementation of the the cairo_t "toy" font API. If family is the zero-length string "", the platform-specific default family is assumed. The default family then can be queried using cairo_toy_font_face_get_family(). The cairo_select_font_face() function uses this to create font faces. See that function for limitations and other details of toy font faces. Since 1.8
Gets the familly name of a toy font. Since 1.8
Gets the slant a toy font. Since 1.8
Gets the weight a toy font. Since 1.8
the main Gtk struct
cairo_t is the main object used when drawing with cairo. To draw with cairo, you create a cairo_t, set the target surface, and drawing options for the cairo_t, create shapes with functions like cairo_move_to() and cairo_line_to(), and then draw shapes with cairo_stroke() or cairo_fill().
cairo_t's can be pushed to a stack via cairo_save(). They may then safely be changed, without losing the current state. Use cairo_restore() to restore to the saved state.