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

Simple Runtime Debugging Message Dialog

At times it's useful to see what values variables hold, or offer some pause point before the code goes elsewhere before causing havoc. Its possible to write output to the terminal but this can get lost in copious forms of other outputs, besides, there's no pausing the script execution either. The following proc creates a custom dialog which displays ad message along with the point in the calling script from which it was invoked. ## simple runtime debugging feedback dialog, alternative to console based gnocl::msg # @param msg message to display # @returns none # proc xxx::msg {txt} { set frame [info frame -1] append msg "Message:\n\n" append msg " $txt \n\n\n" append msg "Called from:\n\n" append msg "Proc:\t[lindex [info level -1] 0]\n" append msg "File:\t[file tail [dict get $frame file]]\n" append msg "Line:\t[dict get $frame line]\n" gnocl::dialog \ -type info \ -text $msg

Creating a button box with right aligned widgets

The dialog widget has its own internal functionaluty to create and position buttons at the bottom right corner of the window container. When creating these for ourselves it must be born in mind that default settings for fill and expand are both 0.5. Failing to set these will always place the child objects in the centre, regardless of alignment. For most cases these defaults are acceptable but, to create that dialog-button arrangement, use the following snippet as a model!   # to right align completely, set expand and fill to 0 set hbox [gnocl::hBox] set b1 [gnocl::button -text Select \                -data $lst                 -onClicked { puts DO-SOMETHING-WITH-%d} ] set b2 [gnocl::button -text Cancel -onClicked { puts DONE! } ] $vbox add $hbox -expand 0 -fill 0 -align right $hbox add $b1 $hbox add $b2