Files
go3270/example5/normalscreen.go
T
Matthew R. Wilson b6fa48f37f Alternate screen size support.
This is a relatively big new feature, which introduces small breaking changes
to the API:

 * NegotiateTelnet() now returns (DevInfo, error) instead of just error.  The
   function signature for the Tx type now has one additional DevInfo parameter.
 * RunTransactions() requires one additional parameter, the DevInfo (which is
   allowed to be nil).

Otherwise, existing behavior continues to work as-is and everything still
defaults to operating on the default 24x80 terminal size.

See example5 for a larger-terminal-aware application.

Pending some time to make sure no new bugs cropped up in this release and that
the alternate screen size support works in the wild, I anticipate this will
become the v1.0.0 release of go3270.
2025-06-29 12:58:18 -07:00

104 lines
3.0 KiB
Go

// This file is part of https://github.com/racingmars/go3270/
// Copyright 2025 by Matthew R. Wilson, licensed under the MIT license. See
// LICENSE in the project root for license information.
package main
import (
"fmt"
"net"
"strconv"
"github.com/racingmars/go3270"
)
var normallayout = go3270.Screen{
{Row: 0, Col: 28, Intense: true, Content: "3270 Screen Size Example"},
{Row: 2, Col: 0,
Content: "This screen is using the default size that all terminals support, 24x80."},
{Row: 3, Col: 0,
Content: "But I know the following information about your particular terminal:"},
{Row: 4, Col: 0, Content: "Terminal Type . . ."},
{Row: 4, Col: 21, Name: "termtype", Intense: true},
{Row: 5, Col: 0, Content: "Rows . . . . . . . ."},
{Row: 5, Col: 21, Name: "rows", Intense: true},
{Row: 5, Col: 28, Content: "(but currently using 24)"},
{Row: 6, Col: 0, Content: "Columns . . . . . ."},
{Row: 6, Col: 21, Name: "cols", Intense: true},
{Row: 6, Col: 28, Content: "(but currently using 80)"},
{Row: 8, Col: 0, Content: "To visit a large sized screen, press"},
{Row: 8, Col: 37, Content: "PF1", Color: go3270.Yellow, Intense: true},
{Row: 9, Col: 0, Content: "To exit and disconnect, press"},
{Row: 9, Col: 30, Content: "PF3", Color: go3270.Yellow, Intense: true},
// a blank field for error messages
{Row: 11, Col: 0, Intense: true, Color: go3270.Red, Name: "errormsg"},
}
func normalscreen(conn net.Conn, devinfo go3270.DevInfo, data any) (
go3270.Tx, any, error) {
rows, cols := devinfo.AltDimensions()
termtype := devinfo.TerminalType()
// Make a local copy of the screen definition that we can append lines to.
screen := make(go3270.Screen, len(normallayout))
copy(screen, normallayout)
// We'll start writing "data lines" at row 13 up to 24
for i := 13; i < 24; i++ {
newfield := go3270.Field{Row: i, Col: 0,
Content: fmt.Sprintf("This is data row %d.", i-12)}
if i == 23 {
newfield.Content += " (The last.)"
}
screen = append(screen, newfield)
newfield = go3270.Field{Row: i, Col: 80 - 5, Content: "<**>"}
screen = append(screen, newfield)
}
fieldValues := map[string]string{
"termtype": termtype,
"rows": strconv.Itoa(rows),
"cols": strconv.Itoa(cols),
}
// We can call the old HandleScreen(), or we could have used the new
// HandleScreenAlt() and provided a nil DevInfo.
resp, err := go3270.HandleScreen(
screen, // the screen to display
nil, // (no) rules to enforce
fieldValues, // pre-populated values in fields
nil, // keys we accept -- validating
[]go3270.AID{ // keys we accept -- non-validating
go3270.AIDPF1,
go3270.AIDPF3,
},
"errormsg", // name of field to put error messages in
1, 1, // cursor coordinates
conn, // network connection
)
if err != nil {
return nil, nil, err
}
switch resp.AID {
case go3270.AIDPF1:
// Go to big screen size transaction
return bigscreen, nil, nil
case go3270.AIDPF3:
// Exit
return nil, nil, nil
default:
// re-run current transaction
return normalscreen, nil, nil
}
}