Editing Tektronix 4010 (section)

===Changes in 4014 model===
The 4014 series had a number of minor changes and some more major improvements.

In alpha mode, the font could be scaled to produce a number of different line sizes. The original 4010-style 35 lines by 74 characters was the default, or could be selected specifically with {{keypress|Esc|8}}. {{keypress|Esc|9}} drew smaller glyphs to produce 38 lines of 81 characters, {{keypress|Esc|:}} for 58 by 121, and {{keypress|Esc|;}} for 64 by 133. All of these could be mixed on-screen.{{sfn|Tektronix|1974|p=3-24}}

In the 4010, the cursor and graphic crosshairs were interactive and used ''dark mode'' to move about the screen without writing to memory. This was accomplished by writing with less energy in the beam, just enough to be seen but not enough to store it. The 4014 added escape codes to allow the user to select this mode deliberately by sending any of the sequences from {{keypress|Esc|p}} through {{keypress|Esc|w}}. This was especially useful in graph mode, as it allowed the system to draw movable objects, although at the cost of having to continually refresh them over the serial link at about 30 times a second in order to avoid flicker.{{sfn|Tektronix|1974|p=3-25}}

This capability could be used, for instance, by drawing the outline of a gauge and its scale markers normally to cause them to store, and then drawing the needle interactively using dark mode. It could also be used to move the graphics cursor to a new location without having to exit and re-enter graphics mode, which previously was the only way to accomplish this.{{sfn|Tektronix|1974|pp=2-8, 2-9}} Sending {{keypress|Esc|h}} through {{keypress|Esc|o}} set the terminal to ''defocussed mode'' which drew at reduced intensity by making the beam slightly wider and spreading the displayed line over a wider area. Finally, {{keypress|Esc|`}} through {{keypress|Esc|g}} returned the terminal to the normal storage mode.{{sfn|Tektronix|1974|pp=2-8, 2-9}}

The 4014 made a change to the way graphics points were entered by adding an ''execution character'' which denoted that a particular coordinate was complete. This allowed, for instance, the X or Y coordinate to be changed without changing the previously stored location for the other. This was useful for drawing boxes or especially a series of lines like an axis, or drawing a point on the screen by sending in the same address as the one last stored or moved to using dark mode. Since the X and Y coordinates used separate characters, the terminal would still notice a sequence of coordinates being sent in the older 4010 format, and draw them as they arrived, providing backward compatibility.{{sfn|Tektronix|1974|p=F-4}}

With the Enhanced Graphic Module installed, an additional set of features were available. Primary among these was the addition of ''12-bit addressing'' which increased the resolution to 4096 by 4096, again with the upper section of the Y axis above 3120 being unseen. Any address could be sent in 12-bit mode simply by sending in an ''extra byte'' between the high and low Y characters, using the same character range as the low-order Y addresses. On a 4010 series terminal or 4014 without the Enhanced Graphic Module, this extra byte would then immediately be overwritten by the actual low-order address that arrived as the next character, and thus have no effect. With the Enhanced Graphic Module, the terminal would use bits 1 and 2 to add to the front of the normally 5-bit high-order X address, and bits 3 and 4 to add to the high-order Y address.{{sfn|Tektronix|1974|p=F-4}}

Another feature of the Enhanced Graphic Module was circuitry that periodically interrupted the beam as it was drawing a vector, allowing the creation of dashed lines. There were five patterns in total; lines, dots, dash-dot and short and long dashes. These were useful for drawing axes and scales, especially when combined with the defocussed mode to lower the intensity, and using the change-one-coordinate feature to quickly draw them. These were selected using the same escape characters as the drawing mode selection of the normal 4014, the range {{keypress|Esc|`}} through {{keypress|Esc|w}}. For instance, without the Enhanced Graphics installed, sending any character from {{keypress|,}} to {{keypress|d}} selected normal line drawing mode, while with the module installed {{keypress|,}} was normal drawing, {{keypress|a}} was normal with dotted lines, and so on.{{sfn|Tektronix|1974|p=F-6}}

Incremental plot, entered with the ASCII Record Separator (RS) character, replaced the normal coordinates with single-character directions. For instance, sending {{keypress|E}} moved up ("north"). This was especially useful for drawing control needles and similar moving displays, and greatly reduces the amount of information that has to be sent to the terminal over time.{{sfn|Tektronix|1974|p=F-7}}

The Enhanced Graphic Module introduced two [[point plotting]] modes. Entering the normal ''point plot'' mode with the ASCII File Separator (FS), instead of RS for graph mode, plotted only the points at the coordinates being sent, not the vectors between them. ''Special point plot'', entered with {{keypress|Esc|FS}}, added an ''intensity character'' to the coordinate that allowed the points to have various brightnesses and optionally defocus the beam.{{sfn|Tektronix|1974|p=F-8}}