“The heart of the melody can never be put down on paper.”
—Pablo Casals
 
Chroma Basics
This chapter describes the features of Chroma keyboard windows. If you are running System 7, you may also wish to refer to Chroma’s balloon help.
A Chroma keyboard window resembles a real synthesizer keyboard. The three main sections of the keyboard are the piano keys, the MIDI channel buttons, and the MIDI controller.
 
Piano Keys
The piano keys have two functions: displaying incoming MIDI notes and playing notes.
When displaying incoming notes, Chroma allows you to see a piece of music being played. The source of the music may be your synthesizer or another MIDI Manager application. MIDI channel information is color coded and note velocity is indicated by the color bar’s height. The illustration at the top of this section shows the keyboard displaying seven notes on three different MIDI channels.
Playing notes involves clicking the piano keys, and possibly dragging the mouse. The Shift key and space bar are also used to control notes.
The higher up the piano key you click, the larger note–on velocity is sent (1–127), indicated by a large colored bar displayed on the pressed key. Dragging left or right from its initial position will send MIDI pitch bend messages, dragging up or down will send aftertouch messages. Releasing the mouse button releases the note.
There are two ways to sustain notes. Shift-click on a piano key and the note will not release when you release the mouse button. Notes will sustain until they are individually clicked again without the Shift key pressed, or you issue a Notes Off (‚åòK) command.
Second, you may use the space bar like a sustain pedal; pressing it begins sustain, releasing it stops all sustained notes.
Note: A shortcut for turning notes off is to simply click in the background area of the keyboard window.
MIDI Channel Buttons
To set which MIDI channels a keyboard window will display, click on the numbered buttons above the piano keys. Shift–click buttons to select multiple channels.
The small red dot over one MIDI button indicates theCurrent Channel . Notes that you play by clicking on the piano keys are sent on this MIDI channel.
Several Keyboard menu commands affect the MIDI channel buttons:
Use the MIDI Color… command to change the current channel’s color. The color of the modulation wheel (see Modulation Wheel, below) matches the current channel.
The Hide Buttons (‚åòH) and Show Buttons (‚åòU) commands toggle the display of the button set on the active keyboard.
Select All (‚åòA) turns on all MIDI channels without changing the current channel.
MIDI Controller
On the left side of the keyboard window is a slider for sending MIDI controller messages. Dragging the slider will send MIDI controller messages in the range 0–127 on the current channel. The slider also moves whenever incoming controller messages are received on the current channel.
The slider color corresponds to the current channel (see MIDI Buttons, above).
Use the Controller… command to set the MIDI controller number for the active keyboard window’s slider.
The Chroma Menu
 
Saving Keyboard Settings
Use the File menu to open and save Chroma documents. When you save a file, Chroma stores the exact configuration of all currently open keyboard windows. Opening or double clicking on a Chroma file will open new windows using the stored keyboard parameters including screen location, keyboard size, MIDI channels selected, current channel, etc.
The Keyboard Menu
Use the Keyboard menu to create new keyboard windows and change keyboard window settings.
 
New
Choose New (‚åòN) from the file menu to open a new keyboard window. The window opens with the current keyboard settings (see the Make Default command, below).
Close
Close (‚åòW) the frontmost keyboard window.
Make Default
Use the Make Default command to set the characteristics of new keyboard windows. The active window’s position, size, selected channels, pitchbend, aftertouch, and background become the new default values.
These settings are saved so that the next time you start Chroma, these settings will remain in effect. The current MIDI channel color scheme is also saved.
Notes Off
The Notes Off (⌘K) command turns off sustained notes. You may also click in the keyboard window’s black area to turn them off. Finally, pressing and releasing the space bar will turn all notes off.
You can sustain notes using either the shift keys or by holding down the space bar.
Show Sustain
When Show Sustain is disabled, incoming sustain messages are ignored for all active MIDI channels on this keyboard. When enabled, notes will stay depressed until a sustain off message is received. Disabling sustain may make notes easier to see when incoming music contains long sustains.
 
Aftertouch
The Aftertouch submenu allows you to choose which type of aftertouch messages are sent when you drag a note up or down.
Chroma supports both Channel key (MIDI message Dx pp) pressure and Polyphonic key pressure (Ax kk pp).
Setting aftertouch to None disables sending any aftertouch messages.
 
Pitchbend
Use the Pitchbend submenu to adjust the sensitivity when dragging a note left or right to generate pitchbend messages.
The choices of One Octave, Two Octaves, etc. correspond to how far the mouse must travel to send the maximum pitchbend (the level ranges from –8192 to +8191). This does not indicate how much pitchbend your synthesizer will actually play, that is normally controlled directly from the front panel of your synthesizer or via MIDI System Exclusive messages.
Setting pitchbend to None disables sending any pitchbend messages.
 
Controller…
The Controller command brings up a dialog to set the MIDI controller number for the keyboard slider (on the left side of the keyboard window.) You can select from Modulation Wheel, Breath Controller, and other standard controllers. Refer to your synthesizer documentation or the MIDI specification for more information about MIDI controllers.
In prior versions of Chroma the controller only sent modulation wheel (MIDI Controller Number 1) messages, which should be suitable for most uses.
The Layout Menu
Use the Layout menu to select the size, width, and background pattern for the active keyboard window.
 
Select from four keyboards widths: 61 Keys, 76 Keys, 88 Keys, or 128 Keys.
When you change a keyboard’s width, the position of the window will shift left or right when it is redrawn. This somewhat unusual action is done so that middle C remains unchanged—in effect the left and right “ends” of the keyboard expand or contract, maintaining proper alignment with other keyboard windows.
 
You can also specify Small, Medium, Large, or Jumbo keyboard sizes. Medium corresponds to the size found in previous versions of Chroma, large is slightly bigger, and jumbo is, well, jumbo (a 128 note jumbo keyboard is nearly 3 feet wide!) Small keyboards work well on small monitors or when you want to see the entire MIDI note range 0–127 on the screen.
Notice the Command key equivalents (‚åò1 through ‚åò8) for keyboard sizes and widths.
 
Background
Select the color or pattern for the keyboard’s background from the Background submenu. This submenu is only available when running in color mode.
Solid Color… brings up a color picker to select a new background color (black, of course, is traditional—but why not lime green?)
The other menu choices offer a number of exciting, beautiful patterns. Some patterns, including Elvis, are from Color MacCheese.
Adding Background Patterns
If you consider yourself a “rugged individualist” (and who doesn’t?), you can customize Chroma by adding your own patterns to those provided with Chroma. To do this, you must be familiar with creating and copying resources using ResEdit.
Note: You should always work on a copy of Chroma, so that you can go back to the original copy if you have problems.
To add a new pattern, launch ResEdit and open the copy of Chroma you wish to edit. Open the 'MENU' #129 resource. You should see a list of menu items including:
Solid Color…#12900
Walnut#12901
Marble#12902
Elvis#12903
...
Add your own menu to this list, including the pound sign, followed by the number. For example, you might add
Dark Side of the Moon#12909
Next, create a pixel pattern 'ppat' resource with ID equal to the number (12909). You can create the pixel pattern using ResEdit’s built–in editor, or copy it from another source. Chroma may have up to 32 patterns, numbered 12900–12931.
The Channels Menu
Use the Channels menu to control the settings of the MIDI channel buttons on the active keyboard window.
 
Select All
Select All (‚åòA) enables all 16 MIDI channels on the active keyboard window.
MIDI Color…
The MIDI Color… command brings up a standard color picker to set the color of the current MIDI channel. The MIDI channel’s color for all open keyboard windows will be updated.
This menu item is enabled only when a keyboard window is active, and the MIDI buttons are not hidden.
Show Buttons
The Show Buttons (‚åòU) command displays the MIDI channel buttons on the active window.
A Select All (‚åòA) command will show the buttons on the active window if they were hidden.
Hide Buttons
The Hide Buttons (‚åòH) command toggles displaying the MIDI channel buttons on the active window.
When the channel buttons are hidden, the MIDI Color… command is disabled.
