Skip to main content

gnocl::pixMap

The distinction between a GdkPixBuf and the GdkPixMap/GdkBitmap is not to easy to appreciate -at the beginning at least. Its easy to assume that they are the something of the same thing but this isn't quite so. The GdkPixBuf is basically a means of loading imagery into memory where as the PixMap and BitMap objects allow direct drawing. Ok, the pixBuf can be drawn onto a pixel at a time and its contents filled but that's about it. The notion is to handle chunks of data at a more basic level rather than working with the niceties. Would it be more reasonable then, to move some of the image manipulations functionality found the gnocl::pixBuf module to a new module, gnocl::pixMap along with the drawing funcs etc? Both are 'off screen' yet the PixMap object can obtain the drawing surface of specific on-screen objects.
This approach would leave the pixbuf module for the sole process of working with the buffer in terms of composting and input/output.
Whilst it would be nice to find some clear distinctions between graphics packages, the practicality of it isn't that simple. There are many package layers, some of whose compenent functions have counterparts elsewhere. The challenge then, lies in deciding which area of functionality is best included in which gnocl package.

Comments

Popular posts from this blog

gnocl::calendar

Given this module some attention today. Added some of the more package wide options to the module and created customised handler for setting the month. (For some odd reason months are are counted 0-11 whereas days are 1-31.) There's still a little more to do to this one including the addition of code to store diary details. Here's the working test script to show the range of options at work. The percentage substitution string item %e explores something that I've been toying with, the name of the signal/event that initiated the call. Ok, a script can keep its own internal trace but who knows, it might prove useful. #--------------- # calendarTest.tcl #--------------- # Author:   William J Giddings # Date:     07/05/09 #--------------- #!/bin/sh # the next line restarts using tclsh \ exec tclsh "$0" "$@" #--------------- package require Gnocl set cal [gnocl::calendar] $cal configure -day 8 -month 7 -year 1956 $cal configure -rowHeight 1 -colWidth 1 $ca...

Creating icons from UTF-8 Characters.

Linux distros have heaps of pre-installed icons ready for use. I recently needed to create a toolbar menu which needed to access a set of unique icons which contained single characters. It was, in fact, a pull down menu for the insertion of 'special characters'. The Gtk+ api has complete functionality for creating icons from pixbufs and Gnocl providing convenient access.  Here's a screenshot and the script.     # !/bin/sh # the next line restarts using tclsh \ exec tclsh "$0" "$@" package require Gnocl if { [namespace exists jmls] == 0} {     namespace eval jmls {} } set ::app(specialCharacters)  [list Section ¶ Paragraph § Separator • Left-Arrow ← Up-Arrow ↑ Right-Arrow → Down-Arrow ↓ Root √] proc jmls::charIcon {name ch} {          set pb1 [gnocl::pixBuf new -width 40 -height 40]     $pb1 text \         -position [list 15 30] \         -font [list...

Getting Widget Style Properties

Until the move over to Gtk4, Gnocl is still built against the Gtk 2.21 libraries. One of the inconveniences of Gtk is getting and setting widget style settings which are considered to be set globally by the desktop style settings and not for the programmer to tinker around with. Needless to say, there are times when different defaults are preferred, largely to draw the users attention to 'something a bit different'. The function gtk_widget_modify_font  is a convenience function to set the widget basefont as shown in this snippet from the button.c module,  if ( options[baseFontIdx].status == GNOCL_STATUS_CHANGED ) { GtkWidget *label; label = gnoclFindChild ( GTK_WIDGET ( para->button ), GTK_TYPE_LABEL ); PangoFontDescription *font_desc = pango_font_description_from_string ( Tcl_GetString ( options[baseFontIdx].val.obj ) ); gtk_widget_modify_font ( GTK_WIDGET ( label ), font_desc ); pango_font_description_free ( font_desc ); } Unfortunately, there's no d...