.. _scriptref-dtm: Deformable Template Models (DTM) ================================ A DTM is in my view just a relatively simple way of defining a relationship between several points. Each of these points have a relative offset to each other, and may different in colour, tolerance, area size and shape. A DTM generally consists out of one *Main Point*, and several *Sub Points*. Finding functions for DTM include the usual parameters. For explanation on these, see :ref:`scriptref-finding`. The structure of a DTM looks like this: .. figure:: ../../Pics/DTM.png :scale: 100 % :alt: Structure of a DTM Where each point in a DTM has a colour, tolerance, area size and area shape entity. The main point's *point* is typically ``(0, 0)``, and all the *subpoint* points are relative to the main point. Example of a simple DTM ----------------------- If one was to create his own DTM, he would first have to think of a useful DTM structure. Say: .. code-block:: pascal MainPoint = (123, 456) SubPoint_1 = (122, 460) SubPoint_2 = (120, 450) Then we could create the following MDTM structure: .. code-block:: pascal // Give dtm.p a length of three. // Mainpoint dtm.p[0] = Point(123, 456); // Subpoints dtm.p[1] = Point(122, 460) dtm.p[2] = Point(120, 450) Note that we do not include other variables, such as colour, tolerance, area size and area shape; they are of no importance in this example. However, this code is not very clear about the DTM's points. Better would be to write: .. code-block:: pascal // Give dtm.p a length of three. // Mainpoint dtm.p[0] = Point(0, 0); // Subpoints dtm.p[1] = Point(-1, 4) // 122 - 123 = -1, 460 - 456 = 4 dtm.p[2] = Point(-3, -6) // 120 - 123 = -3, 450 - 456 = -6 As you can see it is perfectly valid to use negative points. Colour and Tolerance -------------------- The colour value of a point in a DTM is just a RGB integer value. Black = 0, Red = 255, White = 16777215, et cetera. The value tolerance decides if a colour is similar enough to the given colour; if this is the case, we say that the colours *matched*. With no Area Size and Area Shape specified we say that a DTM matches if for each point in the DTM, the colour at the relative point matches the colour in dtm with the given tolerance. .. Colour and Tolerance .. -------------------- .. \forall p \in P, \forall t \in Tol, \forall c \in Col : T(C(p), c) \leq t .. With C() defining the colour at the given point, and T() defining the tolerance .. between the two given colours. Area Size and Shape ------------------- Area Size and Shape add that nifty extra functionality to DTM's. *Area Size* defines the area that should all match the colour with the given tolerance. *Area Shape* is currently not implemented, mainly because we haven't found a good use for area shapes. Loading a DTM from a string ---------------------------- It is also possible to load a DTM from a *zipped* string. The details of the algorithm will not be explained here. (Have a look at dtm.pas if you're interested) MDTM and TDTM ------------- One may know DTM's as a different type: .. code-block:: pascal TDTMPointDef = record x, y, Color, Tolerance, AreaSize, AreaShape: integer; end; TDTMPointDefArray = Array Of TDTMPointDef; TDTM = record MainPoint: TDTMPointDef; SubPoints: TDTMPointDefArray; end; The MML provides the two functions *MDTMtoTDTM* and *TDTMtoMDTM* to directly convert between the two types. Main Point and AreaSize / Shape ------------------------------- The main point's area size and shape are not used in the current implementation. It wouldn't be that hard to add them, however. DTMFromString ------------- .. code-block:: pascal function DTMFromString(const DTMString: String): Integer; Load a DTM from a string generated by the DTM Editor. SetDTMName ---------- .. code-block:: pascal procedure SetDTMName(DTM : integer;const name : string); Assign the DTM a name. Very useful for debugging purposes as it allows the programmers to find out what DTMs are not being freed. FreeDTM ------- .. code-block:: pascal procedure FreeDTM(DTM: Integer); Free a DTM identified by *DTM*. FindDTM ------- .. code-block:: pascal function FindDTM(DTM: Integer; var x, y: Integer; xs, ys, xe, ye: Integer): Boolean; FindDTM is the most basic DTM finding function. It takes a box to search in, defined by *x1, y1, x2, y2*; and if the DTM is found, it will set *x* and *y* to the coordinate the DTM was found at and it will also return true. Else, it returns false. Once a DTM is found, it will stop searching. In other words; it always returns the first found DTM. FindDTMs -------- .. code-block:: pascal function FindDTMs(DTM: Integer; var p: TPointArray; xs, ys, xe, ye: Integer): Boolean; FindDTMs is like FindDTM, but it returns an array of *x* and *y*, as the *TPointArray* type. FindDTMRotatedSE ---------------- .. code-block:: pascal function FindDTMRotatedSE(DTM: Integer; var x, y: Integer; xs, ys, xe, ye: Integer; sAngle, eAngle, aStep: Extended; var aFound: Extended): Boolean; FindDTMRotatedSE behaves like FindDTM. Only, it will rotate the DTM between sAngle and eAngle by aStep each time. It will also return the angle which the DTM was found at. Start rotating at StartAngle. FindDTMRotatedAlternating ------------------------- .. code-block:: pascal function FindDTMRotatedAlternating(DTM: Integer; var x, y: Integer; xs, ys, xe, ye: Integer; sAngle, eAngle, aStep: Extended; var aFound: Extended): Boolean; FindDTMRotated behaves like FindDTM. Only, it will rotate the DTM between sAngle and eAngle by aStep each time. It will also return the angle which the DTM was found at. Starts at 0 degrees and alternatives between - and + aStep to search for the DTM. FindDTMsRotatedSE ----------------- .. code-block:: pascal function FindDTMsRotatedSE(DTM: Integer; var Points: TPointArray; xs, ys, xe, ye: Integer; sAngle, eAngle, aStep: Extended; var aFound: T2DExtendedArray) : Boolean; FindDTMsRotatedSE behaves like FindRotatedDTMSE, but finds all DTM occurances. Since one point can be found on several angles, aFound is a 2d array. FindDTMsRotatedAlternating -------------------------- .. code-block:: pascal function FindDTMsRotatedAlternating(DTM: Integer; var Points: TPointArray; xs, ys, xe, ye: Integer; sAngle, eAngle, aStep: Extended; var aFound: T2DExtendedArray) : Boolean; FindDTMsRotatedAlternating behaves like FindRotatedDTMAlternating, but finds all DTM occurances. Since one point can be found on several angles, aFound is a 2d array. AddMDTM ------- .. code-block:: pascal function AddMDTM(const d: TMDTM): Integer; AddDTM ------ .. code-block:: pascal function AddDTM(const d: TMDTM): Integer; Load a TMDTM structure as DTM in Simba's system. (After it is loaded you can use it in FindDTM, etc) AddSDTM ------- .. code-block:: pascal function AddSDTM(const d: TSDTM): Integer; Load a TSDTM structure as DTM in Simba's system. (After it is loaded you can use it in FindDTM, etc) GetDTM ------ .. code-block:: pascal function GetDTM(index: Integer) : TMDTM Returns the TMDTM of the given DTM index. SDTMToMDTM ---------- .. code-block:: pascal function SDTMToMDTM(Const DTM: TSDTM): TMDTM; Convert a SDTM to MDTM. PrintDTM -------- .. code-block:: pascal procedure PrintDTM(const DTM : TMDTM); MDTMToSDTM ---------- .. code-block:: pascal function MDTMToSDTM(Const DTM: TMDTM): TSDTM; Convert a MDTM to SDTM. CreateDTMPoint -------------- .. code-block:: pascal function CreateDTMPoint(x,y,c,t,asz : integer; bp : boolean) : TMDTMPoint; Create a DTM point.