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Graphic Task Windows ==================== Documentation for !GraphTask application version 3.53 15-Aug-1998, for RISC OS 3.1 or later. Issue: 3.12 15-Aug-1998, replaces: 0.10 13-Aug-1990 1.00 23-Aug-1990 2.00 31-Dec-1990 3.00 20-Jun-1991 3.10 14-Dec-1992 3.11 09-Aug-1994 Author: David J Ruck Copyright © DEEJ Technology PLC 1990-1998 Overview ======== The Graphic TaskWindow provides an extension to the RISC OS taskwindow concept by allowing the full use graphics, whilst preserving the ability to run true RISC OS tasks at the same time. Taskwindows are usually managed by a text editor programs such as !Edit, which don't know how to handle graphics or even text positioning codes. !GraphTask knows how to handle all graphics, screen modes and palettes and display them all in a window on the desktop. !Graphtask is aimed at the enthusiast programmer who is able to write small non wimp programs, and would like them to run in a window on the desktop, but does not have the time or the expertise to tackle the complicated and long winded RISC OS windowing operating systems calls. !Graphtask is very useful for someone who has written or bought a large collection of pre-RISC OS or BBC (Model A, B, Master, Compact or Electron) programs which it is not possible to upgrade to RISC OS versions. A Graphic Taskwindow will allow most non-desktop programs to be run in a fully re-sizeable window on the desktop, without stopping the operations of other RISC OS tasks. "Program" is used throughout this document to mean the program running within a Graphic Task window. "Task" refers to a standard windowing program running on the RISC OS desktop. Features -------- Currently some non desktop programs can be made to multitask using the New Taskwindow option from the !Edit create menu (or by the TaskWindow option on the RISC OS 3 Task Manger menu), but this has the disadvantage that the programs must only output pure text. This means that not only pure graphics programs will not work, but also any program which relies on printing at different locations on the screen. !GraphTask extends the text only Taskwindow concept by providing the following enhancements: Multi-tasking The program running in a Graphic Taskwindow does not need to contain any Wimp_Poll calls to multitask, it is automatically run for a small amount of time between the operation of other fully RISC OS tasks. This is transparent to the user and program, except that the program appears to run more slowly. Multi-windows Any number of Graphic Taskwindows may be active at once, but this is limited in practice by how much memory is used by each task and the memory used by the screen for each task. The screen A Graphic Taskwindow provides the program with an environment similar to what it would have running outside the desktop, whilst running in its own window and without affecting other desktop programs. This allows programs to change the screen mode and the colour palette as normal, but for the changes to only affect the contents of its window. The mode and colours used are approximated as closely as possible in the current desktop mode. Cursors A text cursor and text editing cursor are provided, to show where typed characters will appear and to allow the copying of text from other parts of the screen, in the same way as the cursors outside the desktop. This enables easier editing than is available using the taskinput feature of an !EDIT taskwindow. Scaling A taskwindow can be resized and the scroll bars moved in the normal RISC OS manner without affecting the display of the program in the window. Additionally it may be scaled down to give more room on the desktop whilst keeping all of the programs screen visible (albeit smaller), or scaled up to examine small detail, again this does not affect the program. The mouse Some non-desktop programs use the mouse in their operation, to allow these to be used correctly the position of the mouse pointer they read is adjusted so that it is relative to their screen, rather than the desktop screen. This takes into account the position of the window in which the program is running, whether all of it is visible due to use of the scroll bars, and also if the scaling has been selected. Programs compatible with Graphic Taskwindows -------------------------------------------- Most BASIC and machine code programs can be used in a Graphic Taskwindow as long as they; • Are not RISC OS windowing programs. • Do not directly access the screen. • Do not try to re-configure the machine. • Do not claim operating system vectors or use interrupt code. • Do not try to leave the desktop, (!65Host or old PC emulators). Eight bit BBC computer programs which require !65Host will not work, but 65Tube can be used to run Basic or 6502 assembler programs in a Graphic Taskwindow. 65Tube can be entered by typing *EmulateTube from within a taskwindow. Programs which try to redefine the cursor keys or action (OS_Byte 4 / *FX4) will run but not always function correctly e.g. Arm Basic Editor. Programs which use multiple screen buffers to improve graphics updating will run, but will not always give the correct display in the Graphic Taskwindow. Using !GraphTask ================ To start !GraphTask double click on the !GraphTask icon in a filer window, it will then install itself on the icon bar. New Graphic Taskwindow ---------------------- A new Graphic Taskwindow can be created in four ways; the first two are by clicking on its icon or selecting New Task from the iconbar menu. This will create a new taskwindow with no task running except a command line interpreter. The amount of memory initially given to the task will be that specified in the next slot of the Taskmanager display. To alter the amount of memory when the task has been started use the *WimpSlot command. The third way to create a new Graphic Taskwindow is to drag a file or an application directory (of a non desktop application) onto the !GraphTask icon. The program will then automatically load and run in a new taskwindow. Another way is to start !GraphTask from the Taskmanager menu or an obey file, with the names of programs which will automatically start up in their own task windows. e.g. Run !GraphTask Program1 Program2... Errors when starting. Each new Graphic Taskwindow will require memory for both the program and the screen it uses within its window. Graphic Taskwindows usually start in MODE 12 (the program's mode, not the mode the desktop is currently in), if not enough memory is available MODE 0 will be tried, if there is still not enough memory an error will be reported, and no taskwindow will be created. !EDIT or DDE Taskwindows ------------------------ If you have any taskwindows active, either from !Edit, the RISC OS 3 Task Manager or command windows from the Desktop Development Environment (DDE), they will need to be closed before !GraphTask can be run. This is so the !GraphTask can load a special version of the TaskWindow Module enabling the mouse position to be read correctly by programs in the Graphic Taskwindow. If the new TaskWindow module is not loaded !GraphTask will function correctly except, that programs will read the mouse position relative to the desktop rather than to their screens in a Graphic Taskwindow. Normal Taskwindows started from !Edit, the desktop or by DDE commands during or after !GraphTask has been run, will work as normal. Users may wish to replace the module filename TASK from DDE which has been installed in the !System folder with the module GTASK in !GraphTask, (renaming it to TASK), which will enable !GraphTask to be started while DDE commands are active. Dragging files -------------- Dragging a file over to a Graphic Taskwindow will have the same effect as typing in its full pathname and pressing RETURN - useful for programs which ask for filename, or starting new programs in an existing taskwindow. The filename is normally inserted with a newline at the end, but if shift is held a space is appeneded instead. This is useful for executing commands which take more than one filename as parameters. Graphic Taskwindow Menu ----------------------- Pressing the mouse menu button in a Graphic Taskwindow will call up the menu, its entries are as follows; Menu Button When the mouse buttons select and adjust are pressed over a Graphic Taskwindow the program being run can read this, together with the position of the mouse, taking into account the windows position and scaling so it is relative to the programs screen. When the menu button is pressed the window menu will appear, so to enable the program to detect a menu button destined for it, hold the menu button down over the Menu Button entry. The menu will disappear and the program will see that the menu button has been activated. Kill Kill will not close the window, but the program running in it will be killed and memory used by it freed, the program cannot be restarted. Reconnect After killing reconnect will allow another program to run in the same window, memory is claimed from the Taskmanager’s next slot. Suspend This temporarily stops the program from running, without freeing any memory used by it. This is useful to use with the Save screen facility described below. Resume This enables the program to continue after a suspend, it is transparent to the program running. Save screen This brings up a standard RISC OS saver dialog box to save a copy of the programs screen. A full size screen is saved as a sprite file irrespective of how much of the screen is visible in the window or its scaling. Magnify A magnifier box as used in !Paint and !Draw is displayed allowing the screen within the window to be scaled down, to create more room on the desktop whilst still showing the whole screen, or scaled up to examine detail or read small text. Technical details ================= Multi-tasking Multi-tasking is achieved by using a modified version of the taskwindow module. This module allows non wimp programs to be started as RISC OS tasks, the module waits for Null events to be delivered to each task. It then runs the program for a small amount of time before interrupting it and passing control back to other taskwindow tasks, or normal RISC OS tasks via the standard Wimp_Poll SWI. This results in the program running slower than it would outside the desktop, but it is not necessary to rewrite the program to run in a desktop compatible way. Screen handling The output from Graphic Taskwindow programs are redirected to a sprite which can have MODE and palette settings independent of the desktop. The screen is plotted into a window using the OS_SpriteOp and the Colour_Trans module to provide scaling and achieve the closest result to the appearance of the screen if it were running outside the desktop. Output is buffered to prevent excessive redraws of the window, speeding up the processes. The larger the area changed each time, however, the slower the update becomes. Scaling of 1:1 should be used for the fastest update. Users writing programs specifically for Graphic Taskwindows should try to ensure the screen is updated in blocks, rather than drawing at opposite ends of the screen alternatively. Text cursors Text cursor and cursor editing is provided within !GraphTask as it is not automatic when re-directing output to a sprite. Only normal *FX4,0 type control is provided at present. Under extraordinary circumstances the visible position of the text cursor and the position where typed characters appear may differ, this can be cured by changing mode - typing MODE x. Mode changes If at any time a mode for which there is not enough free memory is selected by the program, MODE 0 will be used as default. Mouse position While the pointer is over a Graphic Taskwindow and during any mouse button changes, the !GraphTask and the modified Taskwindow module translates the mouse position so OS_Mouse calls by the program will be relative to its screen, irrespective of the position or scaling of the window. Incompatibilities The majority of graphics programs tested, which do not try to access the screen or perform operations which do not agree with the taskwindow module (OS vector claims, interrupt handling), have been found to work correctly in a Graphics Taskwindow. All VDU commands work correctly, however there are a few small incompatibilities relating to the values returned by the basic functions (and hence OS routines) MODE, POS & VPOS, referring to the desktop screen, which can cause some programs problems. ColourTrans ColourTrans SWI's which rely on the current screen mode and palette (such as ColourTrans_ReturnGCOL) cannot be used from within Graphic Task Windows, as the current screen mode and palette are taken to be that of the desktop. SWI's which allow a mode and palette to be specified should be used, e.g. ColourTrans_ReturnGCOLForMode. Future enhancements ------------------- !GraphTask is being continually developed, future enhancements will include: • Enhanced cursor & function key emulation to allow all *FX4 and *fx224-228 options without affecting desktop programs. This will allow the use of Arm Basic Editor • Interception of OS routines behind BASIC's MODE, POS & VPOS to return values representative of the programs rather than the desktop screen. • Support for multiple screen banks and *FX112/*FX113 switching using multiple output sprites. • Support for ColourTrans to enable the SWI's to work correctly with the mode and palette used in graphic taskwindow. • Faster task input and output by replacing C routines in main program with hand optimized machine code. GraphTask and RISC OS 3.5 ========================= GraphTask will work correctly with the new RISC OS version 3.5. Programs running in the graphic taskwindow should not attempt to change screen mode using the new OS_ScreenMode SoftWare Interrupt as this will cause the desktop to change mode with unpredictable results. Also graphic task windows cannot handle screen modes with more than 8 bits per pixel. End of !GraphTask.!Help