Talk:Link to BLine - Revision history

Zelgadis: Linking to Blines moved to Talk:Link to BLine: Discussion

2008-10-22T14:50:33Z

Linking to Blines moved to Talk:Link to BLine: Discussion

Zelgadis: removed old stuff

2008-10-22T14:49:32Z

removed old stuff

Zelgadis: /* Creating loops */ concretization

2008-03-11T14:00:57Z

‎Creating loops: concretization

Zelgadis: /* Creating loops */ formula

2008-03-07T16:23:50Z

‎Creating loops: formula

Zelgadis: /* Circular references problem */ some thoughts

2008-03-07T09:04:00Z

‎Circular references problem: some thoughts

Zelgadis: removed second realization way, arranged by sections

2008-03-07T06:43:30Z

removed second realization way, arranged by sections

Dooglus at 23:44, 5 March 2008

2008-03-05T23:44:09Z

Dooglus at 21:56, 5 March 2008

2008-03-05T21:56:31Z

Zelgadis: Inverse Duck Manipulation moved to Linking to Blines: More general name

2008-03-04T17:57:22Z

Inverse Duck Manipulation moved to Linking to Blines: More general name

Zelgadis: new idea

2008-03-04T04:43:16Z

new idea

@@ Line 1: / Line 1: @@
 == Circular references problem ==
@@ Line 78: / Line 43: @@
 === Dealing with loops ===
 To be written... if needed to.

@@ Line 65: / Line 65: @@
 # As the user invokes "Link to Bline" command for C2, we detected loop C2->B2->A2->C2. <br> http://zelgadis.profusehost.net/files/synfig/circular_references/cr02.jpg
-# We must solve equation (or system of equations) to determine position of C2 when: a) it laying on Bline A; b) the shape of Bline A determined by position of C2;
+# We must solve  system of equations to determine position of C2 when: a) it belongs to Bline A; b) the shape of Bline A determined by position of C2;
-## Which formula defines the bline shape? <math>(x,y) = (1-u)^3 \cdot (x_1,y_1) + 3 \cdot u(1-u)^2 \cdot (x_{t1},y_{t1}) + 3 \cdot u^2 (1-u) \cdot (x_{t2},y_{t2}) + u^3 (x_2,y_2)</math>, where u - amount on segment [0,1]
+## How such system of equations will look like? See [[Linking to Blines - Equations]].
-## [[Linking to Blines - Equations]]
+# We placing C2 to determined position. So it definitely on Bline A. Blines A, B, C are updated according to new position of C2.
-# We placing C2 to determined position. So it definitely on Bline A.
+# We linking C2 to Bline A. Position of C2 not changed while linking, so all blines not recalculated and Bline A keeps its shape and recursion not taking place.
 # We linking C2 to Bline A. Position of C2 not changed while linking, so all blines not recalculated and Bline A keeps its shape.
 '''Another possible solution (ah-hoc):'''

@@ Line 66: / Line 66: @@
 # As the user invokes "Link to Bline" command for C2, we detected loop C2->B2->A2->C2. <br> http://zelgadis.profusehost.net/files/synfig/circular_references/cr02.jpg
 # We must solve equation (or system of equations) to determine position of C2 when: a) it laying on Bline A; b) the shape of Bline A determined by position of C2;
-## I don't know how to solve it!!!
+## Which formula defines the bline shape? <math>(x,y) = (1-u)^3 \cdot (x_1,y_1) + 3 \cdot u(1-u)^2 \cdot (x_{t1},y_{t1}) + 3 \cdot u^2 (1-u) \cdot (x_{t2},y_{t2}) + u^3 (x_2,y_2)</math>, where u - amount on segment [0,1]
-## Which formula defines the bline shape?
+## [[Linking to Blines - Equations]]
 # We placing C2 to determined position. So it definitely on Bline A.
 # We linking C2 to Bline A. Position of C2 not changed while linking, so all blines not recalculated and Bline A keeps its shape.

← Older revision		Revision as of 09:04, 7 March 2008
Line 36:		Line 36:
	== Circular references problem ==		== Circular references problem ==

		+	As of http://dooglus.rincevent.net/synfig/logs/2008/%23synfig-2008-03-06.log the circular references problem appeared.

		+	In my (Zelgadis) opinion we have 3 problems:
		+
		+	# Detecting loops
		+	# Creating loops (handling detected loop while creating)
		+	# Dealing with loops (handling modifications of linked-to-bline vertices engaged inloops)
		+
		+	=== Detecting loops ===
		+
		+	00:22 < dooglus> it turns out that every node in the network has a 'time last modified' field, so checking that will allow us to detect loops
		+
		+
		+	=== Creating loops ===
		+	While creating loop we have a Circular references problem.
		+
		+	In example http://zelgadis.profusehost.net/files/synfig/circular_references/bline_link_loop_crash.sifz we have 3 blines A,B,C.
		+
		+	http://zelgadis.profusehost.net/files/synfig/circular_references/cr01.jpg
		+
		+	We want to link C2 to Bline A.
		+
		+	But if we do it, C2 will change it's position (it must lay on the Bline A). As result, the shape of Bline C will change and B2 (which linked to Bline C) will move. It will change the shape of Bline B -> A2 will move -> shape of Bline A changed -> C2 not on Bline A. Сontradiction.
		+
		+	We could move C2 to place it on Bline A again but then it'll end up not laying on Bline A again.
		+
		+	So, if we detected loop, we must do linking in special way.
		+
		+	# As the user invokes "Link to Bline" command for C2, we detected loop C2->B2->A2->C2. <br> http://zelgadis.profusehost.net/files/synfig/circular_references/cr02.jpg
		+	# We must solve equation (or system of equations) to determine position of C2 when: a) it laying on Bline A; b) the shape of Bline A determined by position of C2;
		+	## I don't know how to solve it!!!
		+	## Which formula defines the bline shape?
		+	# We placing C2 to determined position. So it definitely on Bline A.
		+	# We linking C2 to Bline A. Position of C2 not changed while linking, so all blines not recalculated and Bline A keeps its shape.
		+
		+	'''Another possible solution (ah-hoc):'''
		+
		+	# As the user invokes "Link to Bline" command for C2, we detected loop C2->B2->A2->C2. <br> http://zelgadis.profusehost.net/files/synfig/circular_references/cr02.jpg
		+	# We adding a new vertex A3 on Bline A where C2 must be connected. Then we moving (moving, not linking) C2 to the position Bline A where user had clicked. The blines C,B,A will change so C2 probably won't be on A.
		+	# Just link C2 -> A3
		+
		+	=== Dealing with loops ===
		+	To be written... if needed to.

	== Inverse Duck Manipulation ==		== Inverse Duck Manipulation ==

@@ Line 1: / Line 1: @@
 In an [http://dooglus.rincevent.net/synfig/logs/2008/%23synfig-2008-03-03.log IRC discussion] it was suggested that it should to be possible to:
-) Provide an easy way for the user to attach a vertex of a bline to another bline but without the need to create a new vertex over that bline. That allows the simplification of the animation of complex compositions due to the use of less vertices.
+== Provide an easy way for the user to attach a vertex of a bline to another bline ==
 See Yoyobuae's example:
@@ Line 32: / Line 34: @@
 # If was more than one duck selected for linking (i.e. bline vertex duck and bline tangent duck) then the Amount values (in "Bline Vertex"/"Bline Tangent" converts) must be linked  to ensure that they retrieved from the same position on a bline (if changed).
-''' Another possible realization way:'''
+== Circular references problem ==
-Example: We have bline A and bline B. Bline A have vertices A1,A2,A4. Bline B have vertices B1 and B2. To link vertex B1 to bline A between vertices A2 and A4 user must:
+== Inverse Duck Manipulation ==
-# create new vertex A3 between A2 and A4 on bline A. (Insert item (smart))
-# do linking of B1 to A3 as he likes (user can link tangents or not and can define which tangent linked to which)
-# remove vertex A3 (Delete item (smart))
-Result: B1 vertex becomes linked to bline A according to way it was linked to A3.
-) Derived from that request it appears the need to be able to manipulate the ducks that have been converted to a composition. That is: inverse manipulation of valuenodes.
+Derived from that request it appears the need to be able to manipulate the ducks that have been converted to a composition. That is: inverse manipulation of valuenodes.
 For the moment there are some convert types that allow inverse manipulation and only for certain parameters. For example tangents allow inverse manipulation (you modify the x/y position and it calculates the r,theta values. It is know that inverse manipulation leads on some inconsistencies. If the the function that convert a type into other is not biunivocal then it can produce undesired results form the point of view of the final user. For example, the Scale convert type would not have any inconsistency due to it has a easy computable reverse function (the reciprocal)

← Older revision	Revision as of 14:50, 22 October 2008
(No difference)

@@ Line 24: / Line 24: @@
 ## if selected tangent duck, it links with bline tangent at click position
 ### Which one of two? Maybe both? --[[User:Zelgadis|Zelgadis]] 12:27, 3 March 2008 (EST)
 ### We need to scale tangents as in example above
 ## if selected real duck, it links with bline width at click position
 ### currently width value at specific point of bline couldn't be easily retrieved via export/convert combinations --[[User:Zelgadis|Zelgadis]] 12:27, 3 March 2008 (EST)
-# If was more than one duck selected for linking (i.e. bline vertex duck and bline tangent duck) then they Amount values (in "Bline Vertex"/"Bline Tangent" converts) must be linked  to ensure that they retrieved from the same position on a bline (if changed).
+#### [[Convert#BLine_Width]] -- [[User:Dooglus|dooglus]] 18:44, 5 March 2008 (EST)
 ''' Another possible realization way:'''

@@ Line 1: / Line 1: @@
-By a [http://dooglus.rincevent.net/synfig/logs/2008/%23synfig-2008-03-03.log discussion] at the IRC channel it has been requested to be possible to:
+In an [http://dooglus.rincevent.net/synfig/logs/2008/%23synfig-2008-03-03.log IRC discussion] it was suggested that it should to be possible to:
-) Provide easy way for user to attach a vertex of a bline to another bline but without the need of create a new vertex over that bline. That allow simplify the animation of complex compositions due to it needs less vertices.
+) Provide an easy way for the user to attach a vertex of a bline to another bline but without the need to create a new vertex over that bline. That allows the simplification of the animation of complex compositions due to the use of less vertices.
-See Yoyobuae example:
+See Yoyobuae's example:
 [[Image:sif_icon.png|16px]][http://members.lycos.co.uk/yoyobuae/bline_attached_2sections.sifz bline attached]
-In that example there are some vertices converted to Bline vertex and some tangents converted to Bline tangents. Manipulating the exported parameter that represent the position of the vertex along the curve it is possible to easily modify the shape of the composition allowing a better morphing of the shapes created.
+In that example there are some vertices converted to "BLine Vertex" and some tangents converted to "BLine Tangent". Manipulating the exported parameter that represents the position of the vertex along the curve it is possible to easily modify the shape of the composition allowing a better morphing of the shapes created.
-Currently it done through various export/connect manipulations.
+Currently it is done through various export/connect manipulations.
-'''Suggestion:''' It's desired that this attachment be achieve visually, by using the mouse and context menus.  The current method requires the use of exported values and parameter linking, which is less intuitive and also is slower.
+'''Suggestion:''' It's desired that this attachment be achieved visually, by using the mouse and context menus.  The current method requires the use of exported values and parameter linking, which is less intuitive and also is slower.
 '''Possible realization way:'''
@@ Line 31: / Line 31: @@
 ''' Another possible realization way:'''
-The main idea is to change the way how vertex deleting is handled. If vertex deleted and there are other vertices's linked to that vertex, then those vertices are becoming linked to specific position of bline (where deleted vertex was)
+The main idea is to change the way that vertex deletion is handled. If a vertex is deleted and there are other vertices linked to that vertex, then those vertices should become linked to a specific position on the bline (where the deleted vertex was)
 Example: We have bline A and bline B. Bline A have vertices A1,A2,A4. Bline B have vertices B1 and B2. To link vertex B1 to bline A between vertices A2 and A4 user must:
@@ Line 42: / Line 42: @@
 For the moment there are some convert types that allow inverse manipulation and only for certain parameters. For example tangents allow inverse manipulation (you modify the x/y position and it calculates the r,theta values. It is know that inverse manipulation leads on some inconsistencies. If the the function that convert a type into other is not biunivocal then it can produce undesired results form the point of view of the final user. For example, the Scale convert type would not have any inconsistency due to it has a easy computable reverse function (the reciprocal)
-Considering that and taking account that inverse calculation of valuenodes based on ducks position could need some extra computation, it would be good if some convert types can have inverse manipulation.
+Considering that and taking account that inverse calculation of ValueNodes based on ducks position could need some extra computation, it would be good if some convert types can have inverse manipulation.
 '''The proposal is''' that BLine Vertex converted types allow inverse manipulation. So, manipulating a vertex duck you move the attached vertex along the bline and also match the tangent of the attached vertex to the bline's tangent at that position.

← Older revision	Revision as of 17:57, 4 March 2008
(No difference)